I have managed to get the Logitech Quickcam Chat working under Ekiga and Cheese in Ubuntu Intrepid but at night time my images were very dark. And there was no way of adjusting the brightness.
The solution was found here: http://ubuntuforums.org/archive/index.php/t-984126.html. I installed v4l2ucp from http://www.debian-multimedia.org/dists/stable/main/binary-i386/package/v4l2ucp.php. Ran it from the terminal with the command v4l2upc and got a GUI. Exposure was the main setting I adjusted. The frame rate plummeted as the exposure increased (this thread suggests a direct link between the two) so I set it at the slowest frame rate that was satisfactory. I also found that spotlights do not light my face at all well and a side lamp makes the image much, much brighter, thus allowing a faster frame rate.