It also allows you to create "preferred searches", these let you list sites that you want ranked higher in the search results as well as blacklist sites specific to this search.

Just a note, I didn't put too much into handling the url's that get entered so you'll have to look at the about page to make sure you follow a valid format.

Site: http://blacklist-search.appspot.com/

Anyway, this was really a scratch my own itch sort of thing but I thought other people might find it useful as well. I would really appreciate any input as well. Thanks!