My two-year contract with AT&T recently came to and end and I decided to take them up on their recently announced ability to unlock an out-of-contract iPhone. If for no other reason than to make my phone easier to sell to someone who may want to use it on another carrier. Note that this is NOT a jailbreak and has nothing to do with jailbreaking. This process was performed on an un-jailbroken phone that was out of contract (meaning I've paid in full for the phone and now completely own it).
There's a lot of confusion about this process and how it works. There's also no way to verify that your phone is in fact unlocked. Thanks to T-Mobile, you now can for 99 cents. Here's how: