If you've been following this story throughout the day, it's been pretty amusing to see each blogger or news site try to exaggerate what was said more and more. AT&T's CEO made an offhand comment (that may be a trial balloon, may not) that AT&T is going to try and educate consumers about their usage and, if that doesn't help, they'll consider a tiered pricing model. How does that become "AT&T to put a cap on iPhone usage"?
Not to say that I wouldn't drop AT&T like a disease if they did...