Is AT&T happy to assist you in unlocking the phone for usage with other carriers?

I'd be curious about the answer to this one as well. After my O2-UK contract was up, they were as happy as a clam to unlock my phone. All I had to do was plug into iTunes and it just said "iPhone now unlocked" and I wept with joy.

I'm skeptical in the case of ATT though.

Just called AT&T. It's $325 to break contract initially, and $10 less for every month it's in use. They said they won't unlock your phone after you break contract or it ends since "they don't do that for the iPhones"

In the US it was historically "no" for the iPhone.

Wish I could say, but I never asked.