University of California
Univ. Of Cal Berkeley: The Comet's Tale
Site provides extensive information in the study of comets. Includes excellent graphics that depict what comets look like as they travel through the solar system. Also includes information on how comets may have effected the Earth's...
Space.com
Space.com: Comets Data Sheet
This resource explains what comets are, where they come from, and how comets can cause meteor showers.