Couple of days ago, I stumbled across this site called Creativity-Portal.com. It features a bunch of general creativity resources and links, as well as links to a bunch of different "Arts & Crafts" resources, running the gamut from things like macrame and decoupage to drawing, painting, writing, photography, and music.
Two links in particular from the site (actually, I'd seen them before) that I like:
- Art Studio Chalkboard -- particularly their drawing pages which cover perspective, shading, and composition
- Creativity Web -- lots of ways to get your creative juices flowing
And, just because I like it, thought I'd mention a page featuring a number of drawings by Leonardo da Vinci, taken from some of his notebooks -- you can download just the ones you like, or a compressed file (different formats) that has them all.
You might also be interested in the complete translated text of The Notebooks of Leonardo da Vinci.