Websites:

NASA PlanetQuest: http://planetquest.jpl.nasa.gov/
NASA Planetary Fact Sheets: http://nssdc.gsfc.nasa.gov/planetary/planetfact.html
Extreme Science in Space - Our Solar System: http://www.extremescience.com/solarsystem.htm
Franklin Institute Space Science Hotlist: http://www.fi.edu/learn/hotlists/space.php
Atlas of the Universe (Scroll down to "Negative Images" for good printables!): http://www.atlasoftheuniverse.com/
Enchanted Learning Solar System: http://www.enchantedlearning.com/subjects/astronomy/planets/
Nine (Eight) Planets.org: http://www.nineplanets.org/

Books:

Check out our OPAC to find books on your planet!: http://tle.fehb.org/bin/home
Look for books in the nonfiction section with the call number 523!