http://www.princetonol.com/groups/iad/index.html for lesson ideas
http://www.crayola.com lesson ideas and worksheet activities for early finishers
they have online interactive presentations on artists and styles
http://www.dickblick.com/ great sales on supplies and resources for the classroom
http://www.michaels.com/art/online/home lesson ideas and supplies
http://www.enasco.com/artsandcrafts/ supplies and amazing lesson ideas!
http://www.chihuly.com/chihuly.html streaming video of the artist at work and beautiful pictures to share
http://www.moma.org/exhibitions/2001/whatisaprint/flash.html a wonderful interactive presentation on various types of printmaking