Comet sites

http://askville.amazon.com/closest-comet-Earth/AnswerViewer.do?requestId=1092592

http://www.aerith.net/comet/catalog/index-T.html

http://www.physics.ucf.edu/~yfernandez/cometlist.html

http://neo.jpl.nasa.gov/ca/
http://neo.jpl.nasa.gov/ca/historic_comets.html