ATT Internet problems, too many iPhones?

My customer just contacted ATT because their on-call phone hasn't been picking up email today via it's data connection.  ATT said they are having nationwide Internet problems, but didn't specify the cause.

Anyone care to take a stab at the problem?  My guess is that the surge of iPhone inter-tubbers that have never had a real browsers or Internet access has clogged everything up.

My Treo 750 hasn't been able to sync except maybe once today.  I can't imagine what havoc this is causing for business folks that are relying on their data connection today.

Apple seems to have executed beautifully on deployment, but someone forgot to let ATT know that they might have a bunch of new users and data traffic.....