Interesting info:
http://www-db.stanford.edu/~backrub/google.htmlits the university project Sergey Brin and Lawrence Page submitted at Stanford university and later made Google, actually both of them made Google based on another search engine (also project at Stanford university) called backrub (analyzing back links to webpage to figure out which page is important, based on the number of back links)
in this page you can get a brief detail of how Google engine works.....
MaxPaul