Hopefully a class action would be so expensive and such a pain for AT&T that they would just get rid of the caps and drop any overage charges. That's probably not going to happen either. Too bad they didn't implement the meter my school has: it literally doesn't count a good chunk of the traffic. It works.
According to the new terms of service they have implemented binding arbitration and eliminated your ability to file lawsuits as a class.
DISPUTE RESOLUTION WITH AT&T BY BINDING ARBITRATION
PLEASE READ THIS CAREFULLY. IT AFFECTS YOUR RIGHTS.
Most customer concerns can be resolved quickly and to the customer's satisfaction by calling AT&T at 1-800-288-2020. In the unlikely event that AT&T's customer service department is unable to resolve a complaint you may have to your satisfaction (or if AT&T has not been able to resolve a dispute it has with you after attempting to do so informally), we each agree to resolve those disputes through binding arbitration or small claims court instead of in courts of general jurisdiction. Arbitration is more informal than a lawsuit in court. Arbitration uses a neutral arbitrator instead of a judge or jury, allows for more limited discovery than in court, and is subject to very limited review by courts. Arbitrators can award the same damages and relief that a court can award. Any arbitration under this Agreement will take place on an individual basis; class arbitrations and class actions are not permitted. For any non-frivolous claim that does not exceed $75,000, AT&T will pay all costs of the arbitration. Moreover, in arbitration you are entitled to recover attorneys' fees from AT&T to at least the same extent as you would be in court. In addition, under certain circumstances (as explained below), AT&T will pay you more than the amount of the arbitrators award and will pay your attorney (if any) twice his or her reasonable attorneys fees if the arbitrator awards you an amount that is greater than what AT&T has offered you to settle the dispute.
Hmmmm, maybe the state AG's or DPUC's can step in? I'm pretty sure an individual state DPUC could kill the caps, even if it only works for that one state...