If you have a PS/2 mouse then the best place to start would be:
	http://www.netbsd.org/Ports/i386/faq.html#x_and_ps2_mouse

	From there you'll probably end up at:
http://www.netbsd.org/Documentation/kernel/index.html#building_a_kernel

	If you hit any problems or have any more questions - let us know 
	:)

		David/absolute

    "Consistency is the last refuge of the unimaginative." - Oscar Wilde