Select the iPod Touch Settings option from the desktop. Once inside the iPod Touch Settings go to the top of the third section and select General, which is directly above Music. go down to the fourth section and find Passcode Lock, which is right above your setting for Auto-Lock and above that for Restrictions. After you select Passcode Lock you wil be asked to set a four digit Passcode, then to re-enter the same Passcode. Once you do this you will be given a series of options, such as Turn Passcode Off, Change Passcode, when you want to ask for the Passcode, and if you want to erase your data. To turn the Passcode off on your iPod Touch you are going to have to enter the Passcode again. This is a relatively easy process to turn on and off, but if you are the only person near your iPod Touch there may be no reason to set it at all.