I received my Logitech C200 yesterday and it was as small as I thought. I just plugged it in and installed the uvccapture software:
sudo apt-get install uvccapture
Then, I was able to take a snapshot with the following command:
uvccapture -S80 -B80 -C80 -G80 -x640 -y480
To take a video:
ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg
NOTE: the names of the “ff” programs have changed
ffmpeg is now avconv.
ffserver is now avserver.
ffprobe is now avprobe.
ffplay is now avplay.