"The New Drawing on the Right Side of the Brain" by author Betty Edwards
This is a great color resource.
http://www.drawright.com
"The Artist's magazine"
This magazine has wonderful articles on new techniques and materals.
http://www.artsmagazine.com
"Scholastic Art magazine"
This is my main resource for the middle school art projects. Also you find articles on up and coming
young artist.
http://www.scholastic.com