I have a zc0302 webcam, it is not recognized by Arch.
The docs I found says that this camera is supported by zc0301 module.
My camera works fine with Kurumin/Debian etch i386 with zc0301 module.

**The module is at:
/lib/modules/2.6.21-ARCH/kernel/drivers/media/video/zc0301/zc0301.ko

**This module is loaded at the kernel, I put it at /etc/rc.conf

lsmod | grep zc
zc0301 47748 0
compat_ioctl32 9600 1 zc0301
videodev 27008 1 zc0301
v4l2_common 18176 3 zc0301,compat_ioctl32,videodev
usbcore 130864 8 uhci_hcd,zc0301,snd_usb_audio,snd_usb_lib,usbhid,ohci_hcd,ehci_hcd

**It is recognized at the usb port:

lsusb
Bus 001 Device 004: ID 0bda:8187 Realtek Semiconductor Corp.
Bus 001 Device 001: ID 0000:0000
Bus 002 Device 004: ID 0ac8:0302 Z-Star Microelectronics Corp. ZC0302 WebCam

But I don't have the /dev/video0 the udev do not recognize this webcam.

dmesg | tail
usb 2-3: USB disconnect, address 2
usb 2-1: new full speed USB device using ohci_hcd and address 4
usb 2-1: configuration #1 chosen from 1 choice

When I plug at the usb port, the system found it, but don't link to the zc0301 module and don't creat the /dev/video0. I think this could be at the udev rules, /etc/udev/rules.d/udev.rules