Hey there, trying to find good material on art foundation recently and I thought why not share what I found. If you are an artist, art student, or just interested in drawing, painting etc. and you have some good resources too, I'd be happy to hear from you.
Step by Step guide to drawing in Perspective http://design.tutsplus.com/tutorials/how-to-draw-with-perspective--psd-7508
And a good one on "Improve your Art by Learning to See Light and Shadow" which has quite detailed explainations http://design.tutsplus.com/articles/improve-your-artwork-by-learning-to-see-light-and-shadow--cms-20282
I might start some sort of reference page as I go along.