i have a 2 wireless usb mice. also a ps/2 mouse.
the mouse on my leopard 10.5.6 is Inverted...
up=down left = right.
it happened after i installed the gfx string for my 9600 GT nVidia card.
if i remove the string, the mouse is fine,, if i leave it.. the video is fine and i can scroll and move windows.... but my mouse goes all backwards

if you need any details from me to help resolve this.. just message me