Planetary Society
- Pictures and descriptions of famous asteroids, comets, and impact craters.
- http://www.planetary.org/explore/topics/near_earth_objects/asteroids_and_comets/

Welcome to the Planets: Small Bodies
- Contains pictures and brief descriptions of smaller bodies in the universe such as asteroids and comets.
- http://pds.jpl.nasa.gov/planets/choices/smallbod1.htm

Solar System Collisions
- See what would happen if a comet or asteroid hit the Earth or another planet.
- http://janus.astro.umd.edu/astro/impact/