Create a custom search engine with Google Co-op
Google now provides the ability to create a custom Seach Enging through Google Co-op. A simple configuration screen lets you customize your search engine; just enter the words that your search engine will search for or the sites that can be searched. Of course only your friends’ sites will be searched 
You even have the ability to let others help maintain your search engine. by selecting either “Anyone may volunteer to contribute to this search engine.” or “Only people I invite may contribute to this search engine.”
Read the Google Co-op blog.
See Google Co-op at JumpUp.com
