idsketching

I think Henry summed this website up perfectly:

free sketching tutorials. i find video tutorials the next best thing to a real teacher.
for industrial designers or anyone not too busy kerning, who wants to work on their sketching or marker rendering.

 http://www.idsketching.com/ 

 I watched some of these videos n they are super helpful. Its so much easier watching someone draw and imitate rather than trying to use a book or something static.