I have been trying to unlock my Nokia Lumia 900 from AT&T since I'm going to Europe soon for the rest of the year. I called Nokia and AT&T. I've also read a ton of forums. I also had three different 3rd party unlockers try. All of them could not do it. AT&T said they won't be made public until October of this year and one of the unlockers said it's not been made public as well, but didn't elaborate on a time frame. I think AT&T and Nokia subsidized these and want everyone who signed a contract with AT&T to stay put.