You may have been lead to believe that your original iPhone was so dated the radio couldn't handle MMS (Multimedia Messaging Service) even if if Apple and AT&T wanted it to. The truth is out there, and it has arrived in the form of an app available now via Cydia.
ActivateMMS2G is an application that promises to activate MMS capabilities on your original iPhone. The software will specifically NOT work with the iPhone 3G or the 3GS, which are slated to receive MMS support from AT&T later this summer.
To install this software package, you must have an original iPhone that is jailbroken and running iPhone OS version 3.0.
Your mobile carrier must also support MMS. AT&T will not support MMS until later this summer. Unfortunately, if early reports are any indication of what's to come, AT&T will probably never support MMS on the original iPhone.