5 links
Johannes Kepler
johanneskepler.com
Includes detailed biography, online links, outlines of some of his works, quotes, and reading list.
Johannes Kepler and the Music of the Spheres
skyscript.co.uk
An article by David Plant describing Kepler's astrological beliefs.
More Kepler, by Michael Fowler
galileoandeinstein.physics.virginia.edu
Part two of a biography, discussing Kepler's investigations of planetary motion and gravity.