Update (3/22/11): Here is a small painted head study done from the sketch. To speed up the process, I painted my first layers in acrylic and then came back over it in oils for the final coat. I've heard this is not wise since over time (hundreds of years) the oil may flake off, being too thin.
I pulled out the ole 9B pencil for this sketch. Kinda scary at first when you see those dark pencil marks being put on the page, but I needed the contrast for the skin tones.