Chris Scoville has release a Vista gadget that searches System Center TechNet and MSDN conten for you: the System Center Content Search Gadget.
Splogbane: If you are reading this on a blog other than http://blogs.technet.com/tonyso, why not stop patronizing a splog and come over to the original?
Using http://search.live.com/macros/ you can create your own custom search macros. For example, the Terminal Services UA Macro allows you to search just through the Terminal Services docs in the MSDN Library. You can use the side-by-side test page to see your macro's results. When you're satisfied with your macro, you can save it, customize its home page, and then start searching. You can even turn it into Vista gadgets like Chris did.