I found this website: CG Cookie with free, step-by step art tutorial videos.
I say this because I have been looking up and down, left to right and upside down for something like this.
Anyway. I'll admit I skipped the first few lessons because I don't have a graphics tablet, know how to use layers and all that jazz and I wanted to get to the good stuff (note the tendency towards impatience).
The first thing I learned was about lighting
and here's how I did:
Not too shabby (if I do say so myself)