There's another forum discussing this very problem right now. According to them (via a rep named "Duncan" at Apple support):
"When you placed your order from Apple.com, there is a box you must check to even proceed to checkout acknowledging that you will adhere to AT&T Terms of Service, service plans, etc. Then AT&T sends you a supplemental email that you have 72 hours to respond to accordingly. Failure to respond to it sends a code to Apple telling us to cancel your order as you did not agree to these terms and conditions."
Here's the link: http://abs.apple.com/tcat/
I personally did not get any such email from AT&T sending me to that website.
Did anyone else?
"When you placed your order from Apple.com, there is a box you must check to even proceed to checkout acknowledging that you will adhere to AT&T Terms of Service, service plans, etc. Then AT&T sends you a supplemental email that you have 72 hours to respond to accordingly. Failure to respond to it sends a code to Apple telling us to cancel your order as you did not agree to these terms and conditions."
Here's the link: http://abs.apple.com/tcat/
I personally did not get any such email from AT&T sending me to that website.
Did anyone else?