Check out /etc/rc.d/rc.modules (a symlink to rc.modules-2.6.21.5-smp)
Uncomment the relevant lines. The small section below is from the similar file in -current, but the idea is the same (it may be identical - don't have a 12.0 box in front of me):
Code:
### USB device support:
# (Note that once you've loaded USB hub support most USB devices will
# trigger the kernel to load their modules automatically)
# USB "Human Interface Device" driver; handles most USB mice, joysticks,
# gamepads, steering wheels, keyboards, trackballs and digitizers.
#/sbin/modprobe usbhid
# Simple HIDBP USB mouse driver, if hid doesn't work:
#/sbin/modprobe usbmouse
# Simple HIDBP USB keyboard driver, if hid doesn't work:
#/sbin/modprobe usbkbd
by uncomment I mean to remove the "#" from the beginning of the "/sbin/modprobe usbhid" line for example.