A small post just to keep this command at hand:
mplayer -fps 30 -tv driver=v4l:width=640:height=480:device=/dev/video1 tv://
This allows you to watch what your webcam “sees” (provided it uses a video4linux webcam). Btw, Cheese is funny to use too!
I was also trying to find a decent Python library for video4linux but I only found outdated ones (libfg, 2003, and pyv4l, 2002). I guess I’ll have to use some C library for a small project I’ll tell you about later 😉