EvoCam is a really good program. I wanted to set a timelaps of myself sleeping to see how much I actually move around at night since I find myself fairly uncomfortable in my bed. This program would do it with the help of iGlasses which lets you set your iSight to infrared mode. Unfortunately the iSight isn't quite sensitive enough to pick up anything when the room is too dark so it didn't really work.
But anyways, EvoCam will do motion detection and recording.