iRobot Range Finder Help

[Dekabal]

So I want to attach a rangefinder to an iRobot so it can do basic motion sensing. Only problem is, I have no idea how to do that. I was wondering if anyone knows of any tutorials out there that deals with this kind of thing or if anyone who has done something like this could give me a hand. I'm also not sure how i'd pull the data from the range finder and have it be read in my Python program (that's the language I'm using for the robot).