Google have launched a new service called Google Scholar.
Google Scholar enables you to search specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research.
Using it you’ll be able to find articles from a wide variety of academic publishers, professional societies, preprint repositories and universities, as well as scholarly articles available across the web.
Just as with Google Web Search, Google Scholar orders search results by how relevant they are to your query.
In short, Google simply rules search!