Your personal leash can now be untethered. As of Sunday, April 8, if you have an iPhone that is off contract with AT&T, you can unlock the phone.
You have to be eligible, with an account that is current (no outstanding fees). That also means you have to either have a contract that has ended, have upgraded the handset or have paid an early termination fee.
If you fit one of those criteria, you can unlock your phone at the AT&T store, in an online chat with AT&T or by dialing 611 on the phone.
Once you do that, to complete the process, all you have to do is connect the phone to your computer, open iTunes and back up your data and restore the phone to factory settings.