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...
NASA
Nasa Space Science Data Archive: Comet Fact Sheet
This comet fact sheet, supplied by the NSSDC, provides a table of information on selected comets, complete with commentary when appropriate. Includes details of missions to observe these comets.