disable touchpad in Gentoo linux

One last thing: I get pissed off this touchpad etc. It goes nuts sometimes,
gets stuck on the side of the screen, clicking everywhere, and it needs a
vigourous swedish massage to get it back to normal - which can't be good for
my laptop. So I wanted to disable my touchpad. Not as easy it as it sounds.
Went into /etc/X11/XF86Config and deleted everything concerning my normal
mouse, and just left the USB in there (ie. deleted mouse0 in the
"ServerLayout"section and the whole Section "InputDevice" section.
Change the USB mouse in "ServerLayout" section to be
InputDevice "USB Mouse" "CorePointer"
instead of SendCoreEvents (which is a slave).
Now the big trick:
cat /dev/input/mice
You'll notice that both the touchpad and USB mouse spew out gibberish for
this. Not cool for excluding only one.
cat /dev/input/mouse0
Only the touchpad has an effect.
cat /dev/input/mouse2
only the USB mouse has an effect: this is the one we want!
Here's the USB section in /etc/X11/XF86Config

Section "Input Device"
Identifier "USB Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/input/mouse2"
Option "Protocol" "IMPS/2"
Option "Emulate3Buttons" "true"
Option "ZAxisMapping" "4 5"
Option "Name" "AutoDetected"
Option "Vendor" "Autodetected"
EndSection