Unlock AT&T iPhone (http://gsmunlocklabs.com/
Using your IMEI GSMUnlockLabs (http://gsmunlocklabs.com)
Once GSMUnlockLabs notifies you that the iPhone is unlocked you'll need to complete the following steps:
Install or update to the latest version of iTunes
Update your iPhone via iTunes
Insert your new (non-AT&
Wait for your phone to be detected
Disconnect and reconnect the phone and your iPhone is now permanently unlocked!
This "factory unlock" is permanent and your phone will never "relock". This AT&T iPhone unlocking method supports all generations of AT&T iPhones. It could not be easier!
GSMUnlockLabs.com - AT&T iPhone 5 Unlock