MMS may be being released finally to iPhone users on the 25h of September but a guide has been put together so that you guys can all get MMS now, 5 days early!
This only works on OS 3.1.
How to do it (taken from krillr.com):
Mac OS X:
- Close iTunes if it is open
- Start Terminal (Applications > Utilities)
- Run the following command: defaults write com.apple.iTunes carrier-testing -bool TRUE
Windows 2000/XP/Vista (32-bit):
- Go to Start -> Run (
- type in “command” and hit enter
- Type/copy+paste this into the command console that comes up: “C:\Program Files\iTunes\iTunes.exe” /setPrefInt carrier-testing 1
- Hit enter
Windows XP/Vista (64-bit):
- Go to Start -> Run (
- type in “command” and hit enter
- Type/copy+paste this into the command console that comes up: “C:\Program Files (x86)\iTunes\iTunes.exe” /setPrefInt carrier-testing 1
- Hit enter
Download the modified bundle right (right-click and “Save as” or whatever your browser’s equivalent is). To install this, follow these steps.
- Download the file to some location on your computer
- Plug in your iPhone
- Start iTunes
- Click on your iPhone in the device listing in iTunes
- Alt-Click the “Update” button (Shift-click in Windows)
- Browse to where you saved the IPCC you downloaded
- Select this file and click Choose (or OK on windows i think)
- Reboot your iPhone
You should now have a fully working MMS on your iPhone 5 days early. Doesn’t that make you feel special?

I tried this step-by-step and it didn’t work for me. When I tried to find the .ipcc file from shift-clicking ‘check for update’ I was unable to find the file. I had to rename it to .ipsw in order for the iTunes update search to find it… which still didn’t work.
Are you sure you did the first part with the commands in Terminal because thats whats supposed to make it notice the file?
Also, what iTunes version do you have?
Nice, but no IPCC file in that bundle (unless you’re supposed to rename the carrier.strings file.