Users of the iPhone 3G and the iPhone 3GS have been able to enjoy MMS for sometime now (jailbroken and officially), but what about the older iPhone 2G users out there? Well it looks like there may be some help for you. There is a hack there that will allow you to enable MMS for the first gen (or 2G) iPhone. Be warned however, this is still untested and you will be doing this at your own risk. If anything goes awry you can just restore your iPhone and try again. Be sure you back everything up before hand as well!
Here is the process to enable MMS on the iPhone 2G from the hackint0sh.org forums:
Backup original CommCenter (goes without saying…)
Replace CommCenter in: /System/Library/PrivateFrameworks/CoreTelephony.framework/Support/ with the patched one.
Chmod the new CommCenter to 755
Open /System/Library/CoreServices/SpringBoard.app/M68AP.plist and insert a true boolean value for “mms” under capabilities