Figured that I wouldn't leave you Diamond guys in the dark.
http://forum.ppcgeeks.com/showthread.php?t=59218
It has a cab of Arcsoft MMS 5.0.69.44 for sprint. I also made it so that it
removes Sprint picturemail when you install it. Note, It will delete the picturemails on your phone, but you can still go online and get them through the website, and even forward them to yourself if you want them on your phone again.
The default is 512k sending limit, and 10 meg d/l limit. I removed the limit for editing the server setting. Now you can edit the sprint server, and change the limit there in the app without having to do any regedits. You can select 512k (For compatibility with other carriers), 1 meg, and 5 meg.