Well, for future reference at least:
Disables the touchpad, touchpadoff=0 enables it again.
I put that in a script file, added it to the Autostart stuff, and when my desktop starts up, a few seconds later as the autostart files are executed, the touchpad mouse is OFF.
This is handy since I can run another script 'enable-touchpad', which turns it back on (I have a 'toggle-touchpad' too!), which allows me to use the touchpad in the EVER SO UNLIKELY event I've lost my mouse. (I hate touchpad meece!)
blacklisting psmouse certainly works, but removes the possibility of using it in a pinch easily.
I've actually added a hot-key (Win-M) to toggle the state of the touchpad, so when I'm out and about, if I need it, it's just two keys away. (rare, but does happen!)