Good news for those waiting patiently for AT&T to turn on MMS messaging for the iPhone. When it finally does get here, it won’t cost any more than a regular text message, that is, if you subscribe to one of the messaging plans ($5 for 200 messages, $20 for unlimited). From AT&T’s latest PDF faq:

Will AT&T offer MMS and tethering?

Later this summer, as part of the 3.0 software, AT&T will make multimedia messaging (MMS) available at no extra cost to customers with a text messaging bundle. And, in the future, AT&T will offer tethering capability for iPhone 3G S and iPhone 3G.