University of St. Andrews (UK)
University of St. Andrews: Greek Astronomy
Provides an overview of ancient Greek astronomy and the major figures who played a role in developing ideas about the Universe.
Wolfram Research
Wolfram Science World: Pythagoras of Samos (Ca. 560 Ca. 480 Bc)
This site from ScienceWorld provides a short, informative description of many of the contributions of Pythagoras to mathematics. Links exist to some of the contributions as well as to additional information.