I use a Wacom graphic tablet to draw all of the items in the HeroMachine. It cuts development time dramatically, and allows me to combine the art production and code development into one application. I don't think I could ever go back to a pure pen and ink on paper method of drawing at this point, I'm lost to the dark side.
Anyway, I thought you might be interested in seeing a demonstration of how, in general, you can go from a neat photograph of something to a finished digital pen and ink illustration like those found in the program. There's no sound, just a visual -- my auditory skills haven't quite caught up to the times yet.