I have a Logitech Orb webcam which I use to demonstrate Lotus Sametime video for customers. Recently it has been sitting in the corner ever since I moved from Windows to linux and as there is a demonstration due next Wednesday I decided to see what effort was required to get it working on Ubuntu.
After the usual investigation of the support forums I realised I needed to install a UVC (Universal Video Class) driver. Finding the right one could be tricky - however just like envyNG there is a utility to do this for you called EasyCam. the install instructions are here.
As I already had the camera connected via USB the EasyCam software detected it correctly as a "Quickcam Orbit/Sphere MP (2006 model)".
EasyCam then, when prompted, installs the correct driver. Once that has completed you can click "Execute - Webcam" from the EasyCam menu to start streaming video.
Skype picked up on the video straight away.