I see that Pandora has released a Windows Sidebar Gadget themselves.
You can find it here: http://www.pandora.com/on-windowsgadget
I found the Pandora Sidebar Gadget. This gadget lets Pandora live within the Vista Sidebar, thus not taking up (waisting) any valuable taskbar space. This gadget is simple and it just works. Awesome job Brad!
You can download it here: http://www.bgreco.net/gadgets/pandora/