Works okay but uses a non-GPL driver (pwcx) - binary only. Without pwcx there will only be a green screen as output.
Tested with Knoppix 2003-12-11, kernel 2.4.22 . Attach Logitech camera to USB and boot up. Download and install pwcx-8.10 (or newer) from http://www.smcc.demon.nl/webcam/release.html#pwcx and run the command (or similar):
# insmod --force ./pwcx-8.4/2.4.23/gcc-2.95/pwcx.o Warning: loading ./pwcx-8.4/2.4.23/gcc-2.95/pwcx.o will taint the kernel: non-GPL license - Proprietary. See http://www.smcc.demon.nl/webcam/tainting.html
To check the installation run v4l-info and you will see some lines with:
general info VIDIOCGCAP name : "Logitech QuickCam Pro 4000"
To test the webcam you can use xawtv version 3.90 and do a recording by pressing 'r' in xawtv and fill in the form like this.
Recorded movie clips can be viewed with either xine or mplayer.
I'm not sure why but my 850MHz laptop will not record at 15 fps without dropping some frames now and then.