I just posted similar info on other thread too..
I have seen (and I know many people who have done it) remote unlock in eBay. They charge you around 2 bucks and generally takes 12-24 hours. This is factory unlocking so if you update your phone iOS or restore your Phone, it doesn't get locked again. Ever.
Here is one of them...
http://www.ebay.com/itm/Factory-unlock-service-for-AT-T-iPhone-3-3gs-4-4s-5-100-unlocked-/181158101252?pt=LH_DefaultDomain_0&hash=item2a2ddd4104