Wirelessly posted (HTC Diamond: Mozilla/4.0 (compatible; MSIE 6.0; Windows CE; IEMobile 7.11) Sprint MP6950SP)
The pictures and videos that they are talking about is Sprint's Picturemail which I believe is classified by sprint as messaging which obviously includes text messaging.
So those features are not considered part of the internet/data package.
If you use Arcsoft for MMS that is not considered by Sprint as part of Sprint messaging so since it uses your data connection then you should have a data plan if you choose to use it.
If you wanted to use wifi for MMS you would probably have to make adjustments to the application in your devices registry or alter the app itself.
