If you use Quicksilver, you'll like this, it was developed by the same people. It may not be as powerful as Quicksilver, but it has a much friendlier interface:

With Google Quick Search Box you can search for information from just about anywhere. As you type, suggestions will appear that match your query, ranging from applications and local files on your computer, to web search and navigational suggestions, to items from your browser history and contacts - and the types of results you can get will only grow over time!

More from the Google Mac Blog [googlemac.blogspot.com].