this is a beta of google allowing you to create search engines of your own,
you can specify the sites you wish to search, or pages or patterns,
you can decide on how it will look and where the results are displayed,
you can embed it to your site/blog like i did,
and it has the power of Google and its free.
you can checkout my search engine that index Apple2PC and Dev4Mac here.
and you can go and create your own Google Search Engine here.