Sweet Jesus, AT&T just told us that MMS for iPhone launches September 25. Which is emphatically not summer. It'll be coming via software update for iPhone 3G and 3GS (remember, old iPhones are getting left out).
AT&T admits they're late, saying "it was important to give our customers a positive experience from day one" so they needed the extra to "to make sure our network is ready to handle what we expect will be a record volume of MMS traffic." Which I think means if MMS doesn't work, everybody can ream the shit out of them for it. At least it's free.