I admit that I have the dream that I one day will be a reasonalby proficient artist, and it is probably because of that that I enjoy artist's sketchbooks so much. And the only thing I enjoy more that a sketchbook, is a commented sketchbook.
Enter AP Furtado:

My Sketchbook, which was previously a part of the subscriber only, Extras feature on ModernTales, is now available for free at Tweencomix. Come on by and check it out. It’s 20 pages of behind the scenes junk and short glimpses into the closet where more than enough skeletons reside.

Furtado's sketchbook is a delicious treat and while you're there check out his comics as well.