Unlock codes are calculated off of the IMEI number, model of the phone and the carrier to which the phone is locked to. It is entered on the phone in order to remove the restriction set by the...
An unlock code is as simple as it sounds it's a code (e.g. EH8K4C0G74E) that unlocks items for your penguin. At first you type in the code you get with a club penguin toy, game etc. then a book...