This guide will help you retrieve the qc-usb drivers for your Quickcam.
Downloading and installing
Download and install the driver with:
pacman -S qc-usb
If you use an alternate kernel, you can build the module with the PKGBUILD located here yourself.
Finding the module
The module is called c-qcam. Load it with modprobe or add it to MODULES in /etc/rc.conf. Udev should autoload it on reboot, though.
NOTE: If you have a Logitech Quickcam Messenger webcam, you need the qc-usb-messenger package, also in [community].