[Darkjedi]

if you go to the Sprint Power Deck homepage using IE or Opera or whatever, you can check for Software Updates. One of them should be a PictureMail .cab. I didn't know this either until Sprint texted me the day I got my phone about it. Even then they directed me to the wrong link, but I found it in the Power Deck homepage. Hopefully that can fix your issue.

After I installed the update, picturemail worked fine without having to set up anything.

If not, you might have to call Sprint to provision PictureMail service. If its already included on your plan, something might've happened when you transferred phones.