The latest tool to come out of Google Labs will allow you to customize your search results through voting. The way this will work is that, when you do a Google search, you can then designate which results were most useful (thus, raising them higher in your search results next time) or tell Google that certain results were completely wrong (and hide them forever). A link at the bottom of the search results page allows you to completely undo your votes. You would need to be logged into a Google account in order to use this.