This guide will help you retreive the qc-usb drivers for your Quickcam.
1) First, add this line to your /etc/pacman.conf. This will enable another trusted repository that contains the quickcam drivers.
[staging] Server = ftp://ftp.archlinux.org/tur/staging
2) Download and install the driver with:
pacman -S qc-usb24
pacman -S qc-usb26
If you use an alternate kernel (an older one, or an mm series) you can build the module with the PKGBUILD located here.
3) The module is called quickcam