depend on the baseband and the iOS of your iPhone and if you are on the right one, you can jailbreak and unlock your iPhone by downloading and installing ultrasnow from cydia.
Pls tell me the step by step procedure to unlock Iphone 4g having IOS 5.0.1 using sn0wbreeze or ultrasn0w and also provide all the procedure of registration to unlock.
As bab2010 was trying to accomplish before... we need to know what Baseband your iPhone is on in order to assit with Unlocking. Please follow these steps and let us know...