The 16 Personality Types, Descriptions for Self-Discovery by Linda V. Berens and Dario Nardi
There’s a whole series of books by Berens and Nardi, and most of the books are good. Most of them have workbook sections in them, so if you’re looking for materials for staff training on this topic, they’re a good choice.
Some of the stuff on the socionics website seems about fifteen degrees off to me. Some parts of some of the descriptions sound fine, while other parts of the same descriptions sound really bizarre. For example, the coordination thing? Despite their claim that ENFJs are not the most graceful primates, I've always felt that I was fairly well coordinated (except at mealtimes, and then the eye protection comes in handy).
Very cool Simpsonization, by the way. I'm trying to work up the nerve to do it myself, but I'm afraid I'm going to end up looking like a swarthier version of Groundskeeper Willie. :)