I can enter text but it goes out as a "group MMS" according to the top of my message. I am getting complaints from others who, when they receive MMS messages, must go to a website to view them (and it's really just a text).
Weird. I guess it has been this way for me also; I have started getting complaints from from friends with BB's that they have to go to a site to view them. I remember what a paint that was on my original iPhone.
I had this happen to me the other day. I sent out a group message and got a few replies from people saying that there was no attachment to my message... I didn't even send a pic.
Go in to settings then messages and turn 'Group Messaging' off. 'Group Messaging' is a iPhone to iPhone AT&T only feature that you really don't want on unless you message lots of iPhones.