Here are the CORRECT settings to send AND RECIEVE pictures on an iPhone 3g 3.1.3

It took me a few hours to finally get this right!
Cellular Data
APN: internet2.voicestream.com
Username:
Password:
MMS
APN: wap.voicestream.com
Username:
Password:
MMSC: 216.155.174.84/servlets/mms
MMS Proxy: 216.155.165.50:8080
MMS Max Message Size: 1048576
MMS UA Prof URL: http//www.apple.com/mms/uaprof.rdf
Then go to Cydia and add this source:
cydia.pushfix.info
Then in Cydia, go to Sections, then Tweaks scroll to T-Mobile US MMS Fix (its the 3rd one) and install. It says for iOS4 but it worked for me! I've tried the other T-mobile tweaks and they didnt.
I can now actually RECEIVE pictures!!! YAAAAAY! Happy sexting!