If anyone has sufficient programming skills there is already a C# based program that wraps up pandora into a tray applet. It shouldn't be too much work to turn it into a mediaportal addon but I don't have the skill (I realized after 2 years of CS that I had the skill to do scripting level programming and was much more natural as a sysadmin). The app source is at http://openpandora.googlecode.com/svn/trunk/OpenPandora/