Today AT&T turns on multimedia picture messaging for American iPhones. The long-awaited feature will bring AT&T customers up to par with European iPhoners, who have had MMS since approximately the dawn of time, and conventional cell phone owners, who sent six billion MMS texts in the U.S.--in 2006. This past year it exceeded 15 billion. (Below, Swiss MMS, courtesy of renatomitra.)
Newly enabled MMS will precede PC tethering, or Internet-sharing, another long-ago iPhone promise yet unfulfilled (though you can activate it with a simple hack, seen here.) MMS will allow you to send not just photos shot with the camera, but also audio clips, video clips, and contact information. PC World hypothesizes that the influx of new data might overwhelm AT&T's network, but no service interruptions have been reported.