The Make blog has two articles written by Tod E. Kurt & Mike Kuniavsky on how to make interfaces to "drive your Roomba around like a little tank and play music on it."
The enclosure is a floss container. Consumer products have a lot of interesting plastic enclosure styles, and so cheap! This one was something like $2.49. A little time with the diagonal cutters and soldering iron allowed the board to fit.Serial interface Link, Bluetooth interface Link