iPod

Resetting an iPod:
1. Toggle the Hold switch on and off. (Slide it to the Hold position, then turn Hold off again.)
2. Depending on your model, Press and hold the "Menu" and "Select" (Center) buttons simultaneously until the Apple logo appears, or (if you have a different model) Press and hold the "Play/Pause" and "Menu" buttons simultaneously until the Apple logo appears.
You may need to repeat the Pressing and Holding buttons simultaneously step.

If your iPod crashed, you get nothing but a white screen, or it's stuck on the Apple Logo, and Reset doesn't work, this may be the solution you're looking for (depending on iPod model):

1: Plug your iPod into your Computer.
2: Press and Hold the ("Hold" or "Select") and "Menu" buttons (depending on your iPod) until your iPod screen goes Black and shows the Apple Logo, then release the buttons.
3: Wait until your Computer makes a "Chime Sound", which typically takes approximately 5 to 15 minutes.
At which point your iPod should be showing a normal screen. Problem Solved!!!

To Force an Application to Quit:
Press and hold the Sleep/Wake button on top of the iPod touch until a red slider appears, and then press and hold the Home button until the application quits.

To Reset an iPod Touch:
Press and hold the Sleep/Wake button and the Home button at the same time, until the Apple logo appears. (about 10 seconds)

Click this to Try Apples own "iPhone not Appearing in iTunes" troubleshooting Wizard.