Want to turn off the passcode lock but the "Turn Passcode Off" option has disappeared? Been there, done that, reset, restore, and still the option to turn off the passcode is gone.
Microsoft Exchange email is the issue. If you want to turn the passcode off, you must first remove the exchange email account from your ipod touch. Once you delete that email account from your ipod touch, the "Turn Passcode Off" option will reappear.
Yes, it's that simple.