This workaround works for me, Sprint. I'm able to send and the person I send it to receives it, I can receive as well. Below is how I got it working for me... Remember this is a HTC Messaging workaround
Download and install ArcSoft file attached
Download and install Elephant007 Sprint MMS Workaround.cab
Soft reset your phone
After your phone reboots
Select Picture From Albums
----------------Press the
Share icon
--------------Select
Mail
Select
Picture Message(SMS/MMS) ----------Delete the
@; -------------Enter recipients and send
I know there are a few workarounds, this is the simplest for me
I don't know why the
@; is there though
This does not disable HTC Messaging, so you still have the HTC interface for SMS messaging
Hope it works for you, let me know if it did
NOTE: Please let me know if this works or doesn't work for the ROM you are running, give me the name of the custom rom, version and carrier. I will try to keep the status updated with the information