Receive MMS on the iPhone
SwirlySpace, the guys who brought us the MMS app
back in December, have updated to version 0.3, which now lets you receive MMS
This is "very rough" according to them, but a new version will be released soon after which will be much more polished. The good news is - it works. MMS receiving on the iPhone! It should appear on Installer within 24 hours.
You can add this from Swirly's source until Ste gets it up - swirlyspace.com/SwirlySpace.xml
and add version 0.3.2.
A list of carrier settings can be found here
T-Mobile USA's settings are (thanks, insomniaparatus