If your iDevice is out of contract, AT&T will agree to unlock your handset. This process will take anywhere from a few hours to a few days for the unlock code to be issued by Apple. Once this has happened you will receive an email from AT&T for further instructions.
After you receive email notification from AT&T the next process will work for all iPhone models except the iPhone 4S.
Once you’ve done this select Jailbreak and then put your iPhone in DFU mode.
Once your iPhone is in DFU mode and Redsn0w has detected it, you’re ready to proceed.
Uncheck Install Cydia and check Deactivate then click Next. You’re not actually carrying out a jailbreak here, just preparing the handset to receive the activation and unlock code from iTunes.
Once that is done, connect your iPhone to iTunes via a cable and activate it. This will unlock your iPhone while keeping your jailbreak intact.
That’s it you did it!!!!!!!!!!