Kernel 2.6.9 - XF86 4.4.0 - USB Mouse not working
 

After looking at /var/log/messages, it appears that the kernel recognizes the mouse, which makes me think it is xf86 that is giving me the problem. Right after upgrading the kernel, the mouse stopped working - so I updated xf86 thinking that may be the problem. When I use my PS/2 converter the pointer hops around the screen when I move the mouse. When in both modes the light on the mouse is on and the pointer is there...

Print out your XF86Config, XF86Config-4, or xorg.conf. You will have to load up hid and usbmouse. For PS/2 make sure the module mouse is loaded.

I do not have any trouble using with mouse in Slackware 10 and Mandrake 9.0, but on a rare occausion it glitches. It depends what protocol you pick for your mouse.