Nicolaus Copernicus was the Polish mathematician and astronomer who first laid out the proposal that the sun was stationary and was the center of the universe and that the earth revolved around that sun. Because of that theory, he is considered by many to have started the scientific revolution.
Regular Websites
Consists of a biography of the early astronomer, links to other websites which contain information about him, and various news items about him, including the discovery of his remains in 2008. - Nicolas Copernicus
http://www.crystalinks.com/copernicus.html
Nicolaus Copernicus Thorunensis
Sections of this website are dedicated to the pioneering scientist's life story, his discoveries, his book, "On the Revolutions," and a host of resources. - Nicolaus Copernicus Thorunensis
http://copernicus.torun.pl/en/
Scienceworld: Copernicus, Nicholaus
Delves into the life and discoveries of the mathematician and astronomer, including his observations about Ptolemy and his theories and systems. - Scienceworld: Copernicus, Nicholaus
http://scienceworld.wolfram.com/biography/Copernicus.html
Stanford Encyclopedia of Philosophy: Nicolaus Copernicus
This biography includes information about the life as well as the works of Copernicus. Also contains his writings and elucidation on his ideas and an overview of the reactions to "On the Revolutions." - Stanford Encyclopedia of Philosophy: Nicolaus Copernicus
http://plato.stanford.edu/entries/copernicus/
The Galileo Project: Copernicus
Provides the life story of the astronomer, details about his works, and what it was like to be an astronomer during his day. - The Galileo Project: Copernicus
http://galileo.rice.edu/sci/theories/copernican_system.html