My mms on my g2 isn't working.how do I fix it?

Settings => Wireless & network => Mobile Networks => Access Point Names.

Now, hopefully you have T-Mobile MMS. If you do, select the radio button next to it. If there isn't a radio button next to it, then select the name, erase the value for "APN type,", save the settings, and select the radio button.

If you don't have T-Mobile MMS at all, then create a new APN by first pressing "menu." The settings are as follows:

• Name = T-Mobile MMS
• APN = epc.tmobile.com
• MMSC = http://mms.msg.eng.t-mobile.com/mms/wapenc
• MCC = 310
• MNC = 260