Academy Curricular Exchange: Bringing the Solar System to Life - http://ofcn.org/cyber.serv/academy/ace/sci/cecsci/cecsci067.html  How to make a large model to walk kids through the revolutions

Astronomy for Kids: Planets - http://www.dustbunny.com/afk/planets/  A one-page summary for research

Be a Planet - http://rip.physics.unk.edu/Astronomy/Planets(k-1).html  Simplistic lesson

Enchanted Learning: Planets - http://www.enchantedlearning.com/subjects/astronomy/planets/  Great printables and simple research site

Exploring Space with Hands-On Activities - http://www.spacegrant.hawaii.edu/class_acts/  A space grant funded this project with many choices of activities

Hubble Site: Planets - http://hubblesite.org/hubble_discoveries/hstexhibit/planets/  Multimedia

Kids Connect: Planets - http://www.kidskonnect.com/Planets/PlanetsHome.html  Good for in-depth research for gr. 2-3

Magic School Bus: Lost in Space - http://www.eduref.org/cgi-bin/printlessons.cgi/Virtual/Lessons/Science/Astronomy/AST0002.html  A lesson plan based on this book

NASA -
http://pds.jpl.nasa.gov/planets/  Photos of the planets
Starchild (NASA) - http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level1/planets.html  Research site
Solar System Exploration - http://solarsystem.nasa.gov/planets/index.cfm  Research

National Air and Space Museum: Exploring the Planets - http://www.nasm.si.edu/etp/  Includes the explanation of why Pluto is now excluded from planetary status

Planet Coloring Book - http://www.kidsdomain.com/down/mac/solarsyscolor.html  A pdf file to print and use in teaching materials

ProTeacher: Planets –
Edible Planet Lesson - http://www.proteacher.net/archive/posts/2003/03/19/55746.html 
Planet Ad Lesson - http://www.proteacher.net/archive/posts/2001/02/06/14300.html 
Planetary Weather Report - http://www.proteacher.net/archive/posts/2003/07/17/61222.html
Solar System Big Book - http://www.proteacher.net/archive/posts/2001/09/25/20983.html

Solar System Concentration - http://www.theteacherscorner.net/thematicunits/concentration.htm  An idea for making your own concentration game

Solar System in Pictures - http://www.the-solar-system.net/  Incredible images to use for your teaching

Solar System Word Search - http://members.aol.com/lisajg5222/space/solarsystemsearch.html  Printable

The Nine 8 Planets Solar System Tour - http://www.nineplanets.org/  A great research site

Wikipedia: Planets - http://en.wikipedia.org/wiki/Planet  A thorough and accurate research site