Pi Lapse is a simple Python Script for the Raspberry Pi that takes photos at regular intervals.

Pi Lapse currently uses the Raspberry Pi Camera Module but can be changed to run any USB webcam. If you want to use a USB camera I would recommend installing fswebcam on your Pi and changing the line:

subprocess.call("raspistill -w %d -h %d -e jpg -q 15 -o %s" % (image_width, image_height, filename), shell = True)

... with ...

subprocess.call("fswebcam -r %dx%d %s" % (image_width, image_height, filename), shell = True)

An exmaple of a time lapse can be seen here, taken with Pi Lapse.