God, this thread is becoming a circus. The legality of unlocking a phone in the US was never a part of the question in this thread until
markie brought it up. It was not then and is not now relevant to this thread.
These (6) exemptions are only "recommendations" and it would also appear that the exemptions would require submission to Congress for approval and it doesn't look like that has happened. After Congress approves it, then they would become actual exemptions within the DMCA. Just because they announce it, doesn't mean it is in effect. Also, TOS (Terms Of Service) with AT&T doesn't allow the iPhone to be operated on another service carrier in the USA.
Actually, this did intrigue me, though. This is not quite right. This falls under the category of
rulemaking. Each of the branches of government have their own way of affecting the way the law is applied. The legislative branch
writes the bills that become laws in the first place -- e.g. the DMCA did go through them. But both other branches have their chance to interpret (and sometimes interpret ends up meaning modify) the law after it was passed.
The judicial branch can modify the law through case law; depending on the type of stance the case law takes, this would be overridden by new laws at various levels of authority (simple bills or constitutional amendments or whatever) by the Congress.
The executive branch engages in rulemaking. What this means is that after a law is passed, they may promulgate a policy statement explaining how they intend to enforce it. The statement is reviewed by stakeholders and modified, and once the rulemaking is finalized, it instantly goes into effect until it is either superseded by a new rule, the underlying law changes (since the rule is an enforcement of the law), or the court system decides that the rule does not comply with the law, etc.
So the DMCA exemptions
are valid. Here's a more direct source:
http://www.copyright.gov/1201/
U.S. Copyright Office said:
These exemptions went into effect upon publication in the Federal Register on November 27, 2006, and will remain in effect through October 27, 2009.
I had never actually bothered to trace this directly back to the government -- only read it in various electronics news sources... so thanks. I was glad to find out more details myself.

There
are some unanswered things... like what happens in 2009.
But yes, it's irrelevant to this thread, as is the fact that 2G iPhones can be unlocked. The question is how
3G iPhones may be unlocked or obtained unlocked. So far, we have...
- You can buy an originally unlocked (meaning it was sold that way by Apple and the service provider) iPhone from one of the regions where this is available (Hong Kong, etc). As for the question of why AT&T doesn't do this, it was primarily done as far as I can understand because of law and/or market pressure in countries where unlocked phones are the standard (in contrast, they are still unfortunately quite rare here in the USA).
- Apparently there are some regions where an iPhone may be purchased and the service provider will unlock it for you... on Googling, I did not find a lot of supportive evidence for this. It's not that I don't believe it, but again, I'm really curious about what the process for this is. Like in that Australian example, once you call the provider and ask that the phone be unlocked, what happens next?
- You can use a TurboSIM.
iPhones unlocked using all these methods are floating around for sale, but yes, you have to be
extremely careful if you buy one off eBay, since there's really no way to verify what, if anything, you'll receive from the seller.
I'd say the situation is much worse for iPhone 3G's because, while any 3G iPhone
can be unlocked by TurboSIM, there are not millions and millions of TurboSIMs floating around (and I don't even know ... can someone sell it in such a way that you can buy it and reprogram the TurboSIM to match your account without having to buy a TurboSIM programming module yourself?), and
most iPhone 3G's are sold and remain locked. So yeah, not a great situation.