AT&T has MMS, just not for the iPhone. Whenever an MMS is sent you have to log into this bogus website to view the pic/vid. It's honestly retarded.
There are definitely some issues with the iPhone, but I have to say it's by far the best smartphone I've used or seen from friends or collegues. It's already become a platform instead of just a toy and soon, once they get these "new features" ironed out it will be even better. I don't know if it's the complexity of the OS or just Apple being the wankers they've always been, but they have certainly held back on quite a few things.