FOR ANYONE WHO NEEDS IT:

T-Mobile:
APN: epc.tmobile.com
Proxy: [Leave Blank]
Port: [Leave Blank]
Username: [Leave Blank]
Password: [Leave Blank]
Server: [Leave Blank]

MMSC: http://216.155.174.84/servlets/mms
MMS Proxy: [Leave Blank]
MMS Port: [Leave Blank]
MMS Protocol: WAP 2.0
MCC: 310
MNC: 260

-=-=-=-=-=-=-=-=-=-

AT&T:
APN: wap.cingular
Proxy: [Leave Blank]
Port: [Leave Blank]
Username: WAP@CINGULARGPRS.COM
Password: CINGULAR1
Server: [Leave Blank]

MMSC: http://mmsc.cingular.com
MMS Proxy: wireless.cingular.com
MMS Port: 80
MMS Protocol: [Leave Blank]
MCC: 310
MNC: 410

-=-=-=-=-=-=-=-

If you are in the UK or Germany please visit the following link:

http://theunlockr.com/support/internet-mms-settings/