Apple's iPhone has many features other phones don't, but one thing it has been lacking since its launch in 2007 has been Multimedia Messaging Service (MMS) – something even standard phones usually offer. MMS is the ability to send multimedia, such as pictures and videos, to other mobile users like text messaging does, and it's something Apple has promised for a long time, but kept pushing back. The main reason it kept getting pushed back? Network traffic. The iPhone already stresses AT&T's network and MMS would just add to that. But finally, in an official press release, AT&T announced today that MMS would be arriving for iPhone 3G and 3GS customers on September 25, 2009. According to the press release, "the unique capabilities and high usage of the iPhone’s multimedia capabilities required us to work on our network MMS architecture to carry the expected record volumes of MMS traffic and ensure an excellent experience from Day One." It's not all rosy news, however. The other big missing iPhone feature, tethering, received no mention in today's press release whatsoever.