ART:
http://sanford-artedventures.com/  one area of this site has Leonardo's Workshop (interactive)
http://www.sanford-artedventures.com/play/Leonardo/leo_e.html
http://eduweb.com/pintura
http://kinderart.com/    is more for the parent/teacher to get art project ideas from
http://hometown.aol.com/Powers8696/artindex.html   art with lessons that relate to the great artists

ASTRONOMY:
http://skytonight.com/
http://www.the-solar-system.net/

BUY/SELL HOMESCHOOLING STUFF:
http://www.homeschoolclassifieds.com/
http://www.vegsource.com/homeschool/  
http://www.classroomdirect.com
http://www.officedepot.com
http://www.staples.com
http://www.rainbowresource.com/index.php
http:// www.discountschoolsupply.com

http://www.k12.com
www.amblesideonline.com
http://easyfunschool.com
http://funbrain.com
http://brainpop.com
www.enchantedlearning.com
http://www.scholastic.com/
http://www.donnayoung.org/
http://www.homeschoolfreestuff.com/
http://homeschoolreviews.com/
http://homeschooling.gomilpitas.com/
http://www.freehomeschoolsoftware.com/
http://www.homeschooltracker.com/
http://www.edhelper.com/