Google has just unveiled the Google Co-op Custom Search Engine. Well, Custom Search Engine allows you to:

Create a highly specialized Custom Search Engine that reflects your knowledge and interests. Place it on your website and, using our AdSense for Search program, make money from the resulting traffic.

With Google Custom Search Engine, you can restrict sites that appear in your search results or simply give your chosen sites a higher search rank or priority. You can even later add sites for inclusion using Google Marker. Google will give you a piece of code for a search box for you to embed in your site or blog. You can also customize the presentation and functionality of the search engine. Also, you can invite others to co-edit your search engine using the collaboration feature. » Read more: Create a Google Custom Search Engine and Connect to AdSense