It appears that in a bid to settle a class action lawsuit, iPhone carrier AT&T has agreed to release the unlock codes to all of their devices which the exception of course of the iconic iPhone which was probably expected.
Apparently according to a Phone Scoop article by Philip Berne, by way of The Consumerist, there are a few exceptions, the first being an AT&T customer has to complete ninety days of active service and must also provide proof of purchase.
Also if the Big Blue hold exclusivity over the handset for less than ten months the customer must wait until the ten month period is up, and further means that if AT&T holds a longer exclusivity it will never provide the unlock code.
This means of course that it covers the biggest selling smartphone on the AT&T network, the iconic iPhone and thus means anyone with an AT&T iPhone will not be able to port said iPhone to another carrier. They made sure they locked that one down nice and tight didn’t they.