AT&T has now agreed to unlock all of the phones that they offer at absolutely no cost, all except for the iPhone. Most other GSM carriers already offer this so AT&T should probably have been offering it a long time ago, but it is a welcome addition. And the fact that they will not unlock the iPhone was expected, obviously. They will unlock all prepaid phones instantly if you can provide proof of purchase, and all post paid phones if you have at least 90 days of active service. One exception is for phones which AT&T has an exclusivity agreement for. For those phones you will have to wait for at least 10 months since the phone was released.