Though AT&T recently announced its new iPhone unlock program recently, it appears to have been an off-the-cuff decision. The media relations and support web sites and PR papers don't have anything, nor did the staff at the store I visited. Even Apple's list of carriers, which specifies which ones require locks, shows no changes.
Apparently, the phone needs to be off contract, or you need to have paid a termination fee to break the contract.
On the iPhone, go to Settings | General | About and write down the IMEI number.
The author didn't have this easy a process in unlocking his phone. Click here to read about what he went through.
Call AT&T customer service. Be prepared with the phone number, account holder's name and the last four digits of the account holder's social security number (or have some other way of verifying that you are the rightful owner).
Once the information has been confirmed, they will list the phone as being unlockable in Apple's database. Though reports say it can take as long at 96 hours, most appear to be done within a few minutes.
Connect the phone to the computer and run iTunes. Verify that you can get to the Internet, so iTunes can get the unlock file from Apple.
Backup the phone
Restore the phone
Barring complications, the process should take just a few minutes.
Apple has a support document which describes troubleshooting steps for problems which sometimes arise with unlocked iPhones.
InformationWeek's Eric Zeman asks whether it's worth it to businesses to unlock their iPhones. Click here to read what he has to say,.