You can permanently include and exclude sites with Google Custom Search (http://www.google.com/cse/ http://www.google.com/cse/). I added mine to my iGoogle page

You can permanently include and exclude sites with Google Custom Search (http://www.google.com/cse/ http://www.google.com/cse/). I added mine to my iGoogle page so I do all my searches from there instead of google.com. Currently, I blacklist: answers.yahoo.com slideshare.net scribd.com bigresource.com experts-exchange.com