I was watching an internal presentation about Live Search today and ran across this really cool feature. Live and Google have supported searching within a particular domain for quite some time. However, it has always required remembering the correct syntax and typing in the full domain name. Now, Live.com has it integrated into their search results. It's much more readily available than before. Try this:
1. Go to www.live.com
2. Type in a search. Try "msdn blogs".
3. In the upper right hand corner of the results window there will be a slider bar. Slide this to the right (4 horizontal lines).
4. Click the words "Search within this site."
5. Type in a search. Try "unit tests".
The results are everything within blogs.msdn.com that matches your criteria.