There are plenty of similar services that helps you find potential users to follow on twitter. But still , Google Labs as an experiment , is up with a service called Follow Finder that can analyze your following and follower lists and fetch you with tweeps whom you might like and with similar followers.
The service is pretty simple and nothing much is there to count on.You just feed in your twitter handle ( username ) and you get the results based on their algorithm.When we fed our official handle @Blogsdna , follow finder presented us with the below result: