From the Official Google Blog:
Wouldn’t it be cool if you could easily build a search engine on your blog or website tailored to the topics and areas you know and love the most? You’re not alone if you’d like that — we’ve heard from partners large and small, and users across the web who want access to the Google search platform, and want to customize and make it their own.
We’re thrilled to tell you that the search for your own search engine is over. Today we are launching the Google Custom Search Engine. As you might imagine, it’s a simple and straightforward product to use and understand. In a matter of minutes you can create a search engine that reflects your knowledge and interests; looks and feels like your own; and, if you choose, you can make money from the traffic you receive through Google’s AdSense program. You can even invite your friends and trusted community members to add to and help build your search engine.