Okay so I've spent the last 3 days trying everything to get MMS to work. 1) Restoring and jailbreaking 2) Restoring and not jailbreaking 3) Every carrier update file. 4) Resetting settings. 5) Calling ATT to remove and readd all my settings. 6) Creating a media.net account I tried every combination of things too and I figured out what the problem was. I had the original iphone and when I upgraded to the 3g I never called ATT to change my IMEI and ICCID numbers. (Settings>General>About) Today I called and they had my old information. I read them my current IMEI and ICCID numbers and they changed it. The only crappy part was I was on the old data plan and now I'm on the new one paying 10 bucks more a month. Anyway after she put the right info in, I restarted my phone and it worked right away! I hope this helps!