iPod is disabled connect to itunes

My son is having a problem with his iPod.

On switching it on he gets the error message iPod is disabled connect to itunes, but the ipod can't connect to itunes. When itunes opens he gets the error message 'itunes could not connect to the ipod because it is locked with a passcode'. I have tried turning it off holding both the off buttom and home key but it doesn't help. Any suggestions will be appreciated ...