When Apple announced the third version of their iPhone OS earlier this year, there was much excitement; unfortunately though, some of this excitement turned into disappointment. Yes, some handy new features were added, but also some that people believe should have been there from the beginning... MMS being one of those. To add to the frustration from American users, Apple stated that MMS for the U.S. would be delayed due to issues on AT&T's end. Fortunately, that period of MMS drought is quickly coming to an end, and has already done so, according to a post at TUAW.
The author of the article, Michael Jones, apparently has had MMS enabled on his iPhone for an unknown period of time, only having discovered it once a friend sent a message to his phone. What's strange about this is that the service isn't meant to go live until September 25, meaning that it's being on for some almost 2 weeks early. Even stranger is that TUAW has been getting tips from people stating that their service has been working from over a month ago, so AT&T are certainly showing that they want to get this working correctly to please customers.
If you're on AT&T and in the U.S., give MMS a shot now and see how you go. You might need to play around with carrier settings, but never-the-less, it might work. Also, be sure you're running the latest iPhone OS, 3.1, as most people are finding luck with that (it includes the latest carrier settings).