Running 8.0 on IBM T21 laptop and I can't get my MS Intellimouse (with intelliEye) to work via USB.
It works in the PS2 port.
It works as USB under Windows XP on the same machine.

I tried selecting the Intellimouse USB setting with redhat-config-mouse, but no luck.

Fortunately the trackpoint works so I can use the machine (to write this request)

I tried modeprobe -c | grep mouse and there's no usbmouse
is this a problem?

What is modeprobe anyway? And how does it differ from rpm?

Note, it's not that the mousewheel doesnt work (and I do have the ZAxis... stuff in my config file) the mouse doesnt work at all.

Then go back into your XF86Config and change the mouse driver part to imps2 if it is not already and make sure that you have the proper support in your kernel for usb eg. usb-uhci or usb-ohci modules or compile it in. Try modprobe first since they should be default components of any kernel. SHOULD is the keyword.
IM part of imps2 stands for intellimouse btw.