How to Unlock the iTouch Passcode Without iTunes
If the screen lock feature is enabled on your iPod Touch you can disable it directly from the device. Although it can disabled when connected to iTunes on your computer, the iPod Touch's screen lock settings allows you to deactivate the feature from the iPod Touch.
If you cannot access your computer and wish to unlock the iPod Touch you must manually enter the pass code on the device, followed by disabling the feature to prevent it from locking in the future.
Push the "Home" button on the iPod Touch, and slide your finger against the lock tab to unlock the device.
Enter your four digit pass code using the screen's keypad.
Tap "Settings," "General," "Passcode Lock" and "Turn Passcode Off."
Re-enter your pass code to disable the feature.