You can create your own custom searches in Google, where you limit the results to a user defined set of sites. Dan Appleman has created a .net specific search site.
http://www.searchdotnet.com/
Apparently it's not there anymore
On second looks it seems to have moved to http://www.searchdotnet.com/
Not sure if it changed, or I just posted it wrong in the first place. The link is fixed now. Thanks for the note.