Not to rain on the parade, but *where* have AT&T announced this? There's no link in the article, previous posters have said that AT&T support staff don't know about it yet, and the web site still says that, as per the terms and conditions, iPhones CANNOT be unlocked. Now, we all know that is and always has been a lie because there's been a thriving market in jailbreak & unlock hacks for iPhones, but so far, I can't find the official announcement that this policy is reversing on Sunday.
I happy to be proven wrong but I won't believe it until I see people actually getting it done next week.