ok so I just called the AT&T iPhone support line and told them I would be in Europe for about 3 weeks and I would need to unlock my iPhone to avoid costly roaming fee's. This is the quote of the reps answer in the conversation "Because the phone is only provisioned by Apple through AT&T service. Apple has signed a 5 year contract with AT&T that states that no subsidy code will be provided to unlock the iPhone."
I then brought up about the DMCA and the representative researched this through a supervisor and came back with, "The US Copyright Office states that as of Nov 27, 2006 customers have a right to unlock their phone to use on any network so desired. However, The carrier may choose to deny the request on a single model."
To me, I think they made it up to end the phone call but, I haven't read anywhere that proves that they reserve the right to keep the phones locked from the public. If anyone has read this I would really like to see the supporting info. Just for my own knowledge.