Like the iPhone 3G and 3Gs, a print screen on the iPhone 4 is exactly the same. Simply hold down the home key and press the off key. You will hear a camera snap and the iPhone will take it’s own picture!
This is great if you want to e-mail a friend settings for an application or simply a snapshot of your currently installed applications.
A quick way to get the photos off your iPhone is to connect it to your PC, then in Windows Explorer, expand out iPhone and drag and drop any of the photos you want to move.