Mike,
Hey great find! That's Pelusios castaneus, West African mud turtle, it's one of the species that I breed. They are relatively easy to care for but as always you should research as much as possible. I've been working with a buddy of mine on a updating a website focusing on Pelomedusid turtles that should be up and running Jan. 1 2008; Pelusios.com.
In the meantime I would be happy to answer any questions you might have.
Basics:
Water temperature: 26 °C – 28 °C (80-83 °F)
Basking temperature: 32 °C – 35 °C (90-95 °F)
Water Depth: 8 - 20 inches with shallow resting areas is easily handled by them
Diet: These guys are omnivorous and eat large amounts of fresh greens (escarole, dandelion, green leaf lettuce, chicory, anacharis, grape leaves, etc.) and live prey including night crawlers, crickets, and minnows. Mine all accept Mazuri, Aquamax (omnivore), Reptomin, Nasco turtle brittle, also turtle pudding, a homemade gelatin mix.
Regards,
Josh