Of all subjects Pythagoras is probably most covered on the Web. Here's a few links.

http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Pythagoras.html

http://galvin.hypermart.net/history.html

http://www.showgate.com/medea/bulfinch/bull34.html

http://casswww.ucsd.edu/public/tutorial/History.html

You can get more with any search engine.