There are lots of reasons you might want to use a webcam to record time-lapse video. In my case it was to figure out what pest was eating my butternut squash and tomato plants in the garden. I used a 33 ft usb extension cable so I could place an old webcam outside near the plant, and connect it to my old netbook inside the house. In SoCal it never rains so I didn't worry much about the equipment getting damaged, but I didn't want to leave my laptop outside just in case.
I tried several programs. So far all have issues, so I'm open to suggestions. Here they are, sorted in descending order of usefulness (to me).
AVS Video Recorder (Free) worked very well for 30fps video recording with sound, but doesn't have any options to record video without sound, and at a slower frame rate. Mp4/AVC was supported, so the file sizes were manageable if I recorded at 360x240, but it was really hard to see what was going on at that resolution.
Webcam/Screen Video Capture (free) looks real slick, and was able to detect my camera correctly. But it doesn't offer any way to change the fps, and the video formats it can record to are somewhat dated. Plus, the installer was very eager to install ad-ware, though if you read carefully it all could be bypassed.
NCH Debut Video Capture ($40) claimed to be free for home use, but actually only a 3-day limited time demo, and is useless after that period. If it weren't so buggy, this might have worked the best of what I tried, in that it supported arbitrary resolution, frame rates, and even time lapse (10 frames a second, 1 frame a second, or slower, all recorded to MP4/AVC). The killer, however, is that it seems to occasionally write corrupted video to disk, such that any attempt to read the file after the corrupted frame fails. A bit of a show-stopper, that. I think it had to do with dropped frames, but the demo expired before I could fully investigate. I tested version 2.00, maybe they will fix this someday.
Weeny Free Video Recorder - only supports windows media (8/9) and though it advertises custom frame rates, no matter what I entered it recorded at 30 instead. It did support my webcam, but the interface was very buggy, at least under WinXP. I'd avoid this one.
One meta program is ManyCam, which allows you to combine multiple webcams into a single virtual camera. But it didn't work with my old Intel USB Video Camera (failed with no error message). So I can't recommend it.