Logitech Quickcam Pro 9000
The Logitech QuickCam Pro 9000 is an expensive and fairly high-quality webcam that is available in several versions. It is of course and UVC device and as such works out-of-the-box in most cases, but if you want to maximize the usefulness of this device on Arch Linux you'll need to do some magic.
Building the Software
Both applications are built easily using the AUR/ABS build system. In the case of libwebcam I used the patches and build scripts provided by esteemed member whitelynx.
Registering Camera Controls
During the installation of libwebcam the following line will be added to your /etc/udev/rules.d/80-uvcdynctrl.rules
ACTION=="add", SUBSYSTEM=="video4linux", DRIVERS=="uvcvideo", RUN+="/lib/udev/uvcdynctrl"
After the installation, disconnect and reconnect your camera to trigger the rules, then start guvcview once as root, just to let it initialize the AF controls. If you are not yet a member of the "video" group, you should add yourself to it and login anew. After this you should be able to use the cameras full feature set, including autofocus, even as a regular user.