Reports indicate that iPhone users are no longer able to access the AT&T WiFi HotSpot for free through their iPhone. It's not clear if AT&T mistakenly launched the service before it was ready for prime-time (which is possible, given the lack of an official announcement from AT&T), or if the "user-agent spoofing" method to get free WiFi HotSpot access on your laptop caused AT&T to freak-out and pull the plug. The service was clearly intentional, so it's not like AT&T just messed up by allowing iPhone users to get free WiFi for a day.
Here's to hoping that AT&T irons out the bugs (if any) or closes the "user-agent spoofing" loophole and launches the free service soon.