You can use your Blackberry phone to connect to the internet via a computer. (Great for your Laptop) (The settings should work for other phones as well. The speeds are pretty slow but if all you need to do is check your email or do some light surfing it works fine.
All you need is a Blackberry and the data cable that came with it.
The steps below have only been tested on a Windows Vista laptop and a T-Mobile Blackberry Pearl phone. I will attempt to make notes where necessary in order to facilitate substitute settings for other cell providers. You may be able to interpret the settings for Windows XP by following these instructions, and adjusting the appropriate settings. Note: Blackberry Desktop Manager has to be running and your blackberry connected with it's USB Cable for your phone to function as a modem.
Also, this box must be checked in the Desktop Manager:   Enable USB-to-serial converter compatibility

T-Mobile

Step by step instructions:
Phone Settings:
Click Here for Blackberry / Cell Phone APN Set Up
Computer Settings:
1. First you need to have the BlackBerry Desktop Software 4.1 or later installed on your computer.
a. Blackberry Desktop Manager must be running and your blackberry connected with it's USB Cable.
b. Make sure the box is checked in the Blackberry Desktop Managers Connection Options:   Enable USB-to-serial converter compatibility      
2. Set up an Internet APN on your computer:
a. Click: Start>Control Panel>Phone and Modem Options.
b. In the Phone and Modem Options window, click the Modems tab.
c. Select Standard Modem and click Properties.
d. Click on the Advanced Tab.
e. In the Extra initialization commands field, type, or copy and paste the following:   +cgdcont=1,"IP","wap.voicestream.com"
(wap.voicestream.com is T-Mobile's APN. For other cell providers substitute your APN in the quotes where wap.voicestream.com is.)
g. Click OK.
h. In the Phone and Modem Options window, click OK.
3. Now you need to set up a new dial up connection:
a. Click Start>Control Panel>Network and Sharing Center.
b. Click on Set up a connection or network in the left column.
c. Click on Set up a dial-up connection.
d. Click next.
e. Click Standard Modem.
(from here down, if your provider is different than T-Mobile, you will need different settings as required by your cellular provider.)
f. In the Dial-up phone number field put *99#
g. In the User name and Password fields put you’re my T-mobile username and password.
Sample T-Mobile User name: TMobile.com 1234567890
(T-Mobile uses TMobile.com(space - Your Phone Number - 1234567890 represents your phone number in the example above)
Sample T-Mobile Password: (Blank - No Password Used)
h. Click connect.

AT&T
(Refer to the procedure above as a guide and substitute the settings found here)

On your Phone:

APN: wap.cingular
Username: WAP@CINGULARGPRS.COM (case sensitive)
Password: CINGULAR1 (case sensitive)
See List of APN settings for the most common cellular providers in the USA for more settings

On your Computer:

Connection Name: whatever Name you want
Modem: Standard Modem or Bluetooth dialup modem  (if you're using a cable to connect or setting up a Bluetooth connection)
Phone number: *99***1#  (turn dialing rules off)
Username: WAP@CINGULARGPRS.COM  (case sensitive - All Capitols)
Password: CINGULAR1  (case sensitive - All Capitols)
**click advanced tab**
Baud rate: Fast enough to meet or exceed the maximum connection speed of your device. (K (kilo) is thousand, so 19200 is 19.2K)
uncheck wait for dial tone before dialing
Extra dial string: +CGDCONT=1,”IP”,”WAP.CINGULAR”   (case sensitive and that is an O not a zero)
All other settings leave default (port settings, TCP/IP, Servers)
Settings Used in this procedure List:
Username: WAP@CINGULARGPRS.COM
Password: CINGULAR1
Advanced initiation string thing: +CGDCONT=1, “IP”,”WAP.CINGULAR”
Phone number: *99***1#

-------Set up option 2-------

On your Phone:

APN: wap.cingular
Username: WAP@CINGULARGPRS.COM (case sensitive)
Password: CINGULAR1 (case sensitive)
See List of APN settings for the most common cellular providers in the USA for more settings

On your Computer:

Connection Name: whatever Name you want
Modem: Standard Modem or Bluetooth dialup modem  (if you're using a cable to connect or setting up a Bluetooth connection)
Phone number: *99***1#  (turn dialing rules off)
Username: ISP@CINGULARGPRS.COM (case sensitive - All Capitols)
Password: CINGULAR1  (case sensitive - All Capitols)
**click advanced tab**
Baud rate: Fast enough to meet or exceed the maximum connection speed of your device. (K (kilo) is thousand, so 19200 is 19.2K)
uncheck wait for dial tone before dialing
Extra dial string: +cgdcont=1,"IP","ISP.CINGULAR"  (case sensitive and that is an O not a zero)
All other settings leave default (port settings, TCP/IP, Servers)
Settings Used in this procedure List:
Username: ISP@CINGULARGPRS.COM
Password: CINGULAR1 or cingular1
Advanced initiation string thing: +cgdcont=1,"IP","ISP.CINGULAR"
Phone number: *99***1#

-------Set up option 3-------

On your Computer:

Connection Name: whatever Name you want
Modem: Standard Modem or Bluetooth dialup modem  (if you're using a cable to connect or setting up a Bluetooth connection)
Phone number: *99#  (turn dialing rules off)
Username: (Blank)
Password: (Blank)
**click advanced tab**
Baud rate: Fast enough to meet or exceed the maximum connection speed of your device. (K (kilo) is thousand, so 19200 is 19.2K)
uncheck wait for dial tone before dialing
Extra dial string: +cgdcont=1,"IP","proxy"  (case sensitive and that is an O not a zero)
All other settings leave default (port settings, TCP/IP, Servers)
Settings Used in this procedure List:
Username: (Blank)
Password: (Blank)
Advanced initiation string thing: +cgdcont=1,"IP","proxy"
Phone number: *99#

-------Set up option 4-------

Connection Name: whatever Name you want
Modem: Standard Modem or Bluetooth dialup modem  (if you're using a cable to connect or setting up a Bluetooth connection)
Phone number: *99#  (turn dialing rules off)
Username: (Blank)
Password: CINGULAR1
**click advanced tab**
Baud rate: Fast enough to meet or exceed the maximum connection speed of your device. (K (kilo) is thousand, so 19200 is 19.2K)
uncheck wait for dial tone before dialing
Extra dial string: +cgdcont=1,"IP","ISP.CINGULAR"  (case sensitive and that is an O not a zero)
All other settings leave default (port settings, TCP/IP, Servers)
Settings Used in this procedure List:
Username: (Blank)
Password: CINGULAR1
Advanced initiation string thing: +cgdcont=1,"IP","ISP.CINGULAR"
Phone number: *99#

-------a set up procedure -------

Setting up the Connection:

Go to Start, Settings, Control Panel. Double click Network Connections.
Click on Create a new connection.
The New Connection Wizard window appears, click the Next button.
Select Connect to the Internet. Click the Next button.
Select Set up my connection manually. Click the Next button.
Select the Connect using a dial-up modem. Click the Next button.
Select the Standard Modem if you're using a cable between your cell and computer or Bluetooth modem if your connecting to your computer using Bluetooth. Only one device may be selected. Click the Next button.
Type the name you want for this dial up connection profiles name. Click the Next button.
In the Phone number field enter *99#.
NOTE: Phone number can also be entered as *99***1#, or *99***(CID Number)#
NOTE: By default 1 is the CID, but can change. (see list of possible phone numbers below)
Click the Next button.
Enter Username: ISP@CINGULARGPRS.COM (ALL CAPS)
Enter Password: CINGULAR1 (ALL CAPS)
Enter Password again in the Confirm box: CINGULAR1 (ALL CAPS)
Uncheck the following boxes:
Make this the default Internet connection.
Turn on Internet Connection Firewall for this connection.
Click the Next button.
To access this connection quickly from the desktop, check the box to Add a shortcut to this connection to my desktop.
Click the Finish button.

Making the Connection:
Select the icon with the name of your connection. Leave the Username and Password fields blank.
Click on Dial to establish an active connection.
A window will display the status of the connection with the network.

List of AT&T Dial up Phone Numbers to try:

*99#

*99***1#

*99***3#

*998**3#

List of Dial up User Names and Passwords:

user name: WAP@CINGULARGPRS.COM
password: CINGULAR1

username: wap.cingulargprs.com
password: cingular1

username: ISP@CINGULARGPRS.COM
password: CINGULAR1

username: isp@cingulargprs.com
password: cingular1

user name: ISPDA@CINGULARGPRS.COM
password: CINGULAR1

username: ispda@cingulargprs.com
password: cingular1

username: (left blank)
password: (left blank)

Other Settings:

Do not set modem compression.

TCP/IP 4: (required for your browser to find web addresses)

Check: Obtain IP address automatically (default) for both settings.

Here's some settings to try just in case:

DNS1: 208.67.222.222
DNS2: 208.67.220.220

Homepage-http://home
Connection Type-continuous
Connection Option-none
Bearer-gprs
Access Point Name(APN)-wap.cingular
IP address-10.250.250.250
Server Login-wap@cingulargprs.com
passwoard-cingular1

medianet/wap ip 66.102.186.11

default gateway 10.64.64.64 - default IP on pppd

phone number: S=2
username: (Blank)
password: (Blank)

phone number: #777
username: (Your 10 digit mobile phone number)
password: (Your "MySprint Password)
If you do not know your "MySprint" password, go to https://sso.sprintpcs.com/sso/Login.do to create/recover one.

phone number: #777
username: (Blank)
password: (Blank)
When you connect to the internet for the first time it will prompt you with the user name and password screen, don't enter anything and click the check box to save the entry.
You will not be prompted again.

phone number: #2932
Uncheck: Use area code and Dialing Properties.
username: web
password: web

phone number: #7777
username: (Blank)
password: (Blank)

phone number: #777
Username: myusernamehere@modem.sprintpcs.com
password: call tech support get your pass... they can't give it, and NO one knows it, they will have to reset... so you'll choose it at that time. 30 mins later, it will be active.

Dial up Phone Numbers for Verizon:

On your Phone:

No configuration Needed

On your Computer:

Install your modem drivers- look for drivers on your cell phone's web site

Network Connections Settings (computer dial up settings):
Dial number: #777
Username: "your10 digit phone number"@vzw3g.com  (example: 1234567890@vzw3g.com)
Password: vzw

-----Set up option 2-----

On your Phone:

No configuration Needed

On your Computer:

Install your modem drivers- look for drivers on your cell phone's web site

Network Connections Settings (computer dial up settings):
Dial number: #777
Username: (Blank)
Password: (Your 10 digit phone number - no dashes or spaces, just the 10 digits)

-----Set up option 3-----

On your Phone:

No configuration Needed

On your Computer:

control panel>phone/modem>modems>select your phone (standard modem or bluetooth) and hit properties>advanced

initialization string:   at$qcmdr=2
Phone Number: #777
username: qnc
password: qnc

-------------------------

Other Settings:
Select Properties,
Select "Options" tab
Under "Dialing options" check "display progress while connecting", "prompt for name and password, certificate, etc.", and "prompt for phone number"
Select Security tab, Select "Advanced" (NOT typical), Under "Data encryption" select "Optional Encryption"
Under "Login Security" select "Allow These Protocols" and check ONLY "unencrypted passwords (PAP)"
Select "Networking" tab
Ensure that "type of dial up" is set to PPP

List of Verizon Dial up Phone Numbers to try:

#777

*77

*99#

*99***2#

List of Dial up User Names and Passwords:

username: [your 10-digit phone number]@vzw3g.com
password: vzw

username: [your 10-digit phone number]@vzw3g.com
password: VZW

username: [your 10-digit phone number]@vzw3g.com   - try with Phone Number: #777
password: verizon

username: qnc
password: qnc

username: QNC
password: QNC

username: [your 10-digit phone number]@vzw3g.com
password: #777

username: [your 10-digit phone number]@vzw3g.com
password: last 4 digits of your telephone number

username: (left blank)
password: (left blank)

Motorola Phone Note: Enable DUN by quickly entering ##DIALUP

username: alltel.com
password: allltel

QNC
Originally, with QNC/cdmaOne, data calls and voice calls did not significantly impact the network.
This was due to the low availability of data capable phones, and the general lack of desire for them, so, carriers ignored usage.
For this reason, no special authentication was necessary. Even today, one can connect to a dial-up ISP with this method.
Note: Verizon has announced high per-kb charges on QNC use. Avoid using QNC without checking your contract for rates and penalties.

To connect via QNC and use your provider as an ISP, use the following values:
(This taken from Verizon, results may vary on other providers.)

Number #777
Username qnc
Password qnc

Note:
QNC is slow and obsolete, and excessive use is not only expensive, but will alert your carrier that you are using unauthorized services.

1xRTT
1xRTT, and it's 2.5G technology marked the introduction of services that relied heavily on data access.
This also marked the introduction of PCMCIA cellular modems, providing practical speeds for mobile data.
Almost every phone sold since 2002 by CDMA providers has 1xRTT capability.

1xRTT has a more advanced authentication model, and was capable of being billed for "data usage" instead of simple "airtime minutes" by providers. Verizon and Sprint both chose to adopt hybrid plans. Users could pay for data or use airtime minutes.
Current cellular plans use 1xRTT as a backup for when EV-DO isn't accessible, and will bill 1xRTT and EV-DO at the same rate.

To connect with 1xRTT and use your provider as an ISP, use the following values:

Phone number #777
User name <number>@<provider>
Password <pwd>
In all cases, replace <number> with your 10 digit cell phone number: (123) 456-7890 would be "1234567890".
<provider> and <pwd> vary based on your cellular provider.

Verizon:
user name: vzw3g.com
password: vzw

Sprint:
phone number #777
username: your Vision login
password: your Vision password

Alltel:
phone number #777 ?
username: alltel.com
password: allltel

1xRTT is a weak point with most carriers, and an obsolete technology.
Continual use in areas that have known EV-DO coverage will be discovered and billed to you as illegitimate data usage.

EV-DO
EV-DO is the current choice of CDMA providers for data services, and offers significant speed boosts over 1xRTT.
All currently sold phones have EV-DO capabilities, and the vast majority of phones sold in the last three years do as well.

To connect via EV-DO and use your provider as an ISP, use the following values:

Number #777
Username <number>@<provider>
Password <pwd>

In all cases, replace <number> with your cell phone number: (123) 456-7890 would be "1234567890".

<provider> and <pwd> vary based on your provider.

Verizon:
user name: vzw3g.com
password: vzw

Sprint:
phone number #777
username: your Vision login
password: your Vision password

Alltel:
phone number #777 ?
username: alltel.com
password: allltel

EV-DO is the best option for connectivity at this time with CDMA providers.
It is used to deliver many high-bandwidth applications, such as VCAST, and therefore excessive use is more likely to go undetected.

Common Problems:
Getting 1xRTT to Work
If you have a hybrid (1xRTT and EV-DO) phone, the phone will automatically switch from 1xRTT to EV-DO when necessary. Furthermore, hybrid phones have NAIs (covered in EV-DO) that prevent you from manually specifying a username and password when connecting.
To circumvent this, there are two steps.
Disable EV-DO
This is entirely maker specific and occasionally phone specific.
Disable CHAP
There is a security hole in NAI authentication: when using certain forms of authentication, the phone will not replace your username with its NAI, and login may proceed.
First Try - Gain root on the device. Next edit the /etc/ppp/options file. Finally find the line #-chap and change it to -chap.
You should now be able to connect to the internet with your phone.

It is recommended NOT to use 1xRTT on a hybrid phone, as such usage will be immediately suspicious to your carrier.

Getting EV-DO to Work:
EV-DO relies on a Network Access Identifier (NAI) stored in the phone. Your phone will have two (or more) NAIs, one for internal phone data use (mobile web browser, Get It Now, etc), and one for tethered data use (Bluetooth, USB, etc).
Simply setting your tethered data NAI to match your internal phone data NAI will circumvent this protection.

Example: A Verizon phone will use <number>@vzw3g.com for internal phone applications, and will use <number>@dun.vzw3g.com for tethered access. Verizon's servers will then reject your login if you attempt to use <number>@dun.vzw3g.com without a data plan.
Unfortunately, it is not possible to change the NAI directly on most phones.

Palm Centro (Verizon)
As of June 2008 the Palm Centro works out of the box for Bluetooth DUN with a paid data plan through Verizon
Non-Motorola Phones
Please review How to enable EVDO DUN on nearly any phone in 10 easy steps for the details.
Motorola Phones:
Try the following the guide at: How to enable EVDO DUN on nearly any phone in 10 easy steps.
If that fails, it is because your phone is programmed to reset its NAI on reboot to factory settings.
This is most common with recent Verizon-branded Motorola phones.
Also for Motorola phones, check out Mark Venture's Verizon Pages.
If that troubleshooting forum was un-able to help you, you may have better luck checking out HowardForums.

An alternative connection method- Setup a Bluetooth connection between your phone and computer. I am not going to get into this, but you should be able to use the built in Bluetooth features to “pair” Windows to your device. In Desktop Management Connection Settings use Bluetooth. It should appear when setting up a Dial Up Networking Connection under Standard Modem as “Standard Modem Over Bluetooth Connection”

Air Time charges may apply. Exploit free nights and weekends.