I was able to develop an AppleScript Studio application to control my Roomba Vacuum cleaner. (You can get the details at http://www.larryshearon.com/RoombaControl/Application.html). I would be happy to share the scripts with anyone.
I got tired of my Roomba bumping into things so I added a Arduino and a color sensor to follow blue painter's masking tape. Now it stays on the straight and narrow.
Details and source code available here: http://operationsimprovement.net/RoombaControl/Arduino_Version.html
Updated 11/25/09 - Changed the mounting of the color sensor array and made it more fault tolerant due to bluetooth connection failures