i tried that and still no luck, i keep getting the "the media content was not included due to a picture resolution or message size restriction"
did you go back and put the settings in the cellular data network after you edited the file? other than that, i'm not sure. here are the settings that i am using currently.
Cellular Data
APN: epc[dot]tmobile[dot]com
MMS
APN: wap[dot]voicestream[dot]com
MMSC: http[colon]//mms[dot]msg[dot]eng[dot]t-mobile[dot]com/mms/wapenc
MMS Proxy: 216[dot]155[dot]165[dot]50[colon]8080
MMS Max Message Size: 1048576
MMS US Prof URL: http[colon]//www[dot]apple[dot]com/mms/uaprof[dot]rdf
Internet Tethering
APN: epc[dot]tmobile[dot]com
*replace all the [dot] with .
*replace all the [colon] with :
i don't know if it makes a difference or not, but i have a blackberry data plan on my account since that was what i was using before i got my iphone.