I've got a USB mouse (MS) that came with a USB to PS/2 converter. It works fine hooked up to a PS/2 port. I run it through a KVM switch that is PS/2 and not USB so this is necessary. One of the boxen ...

[David] sent in his implementation of reading a PS/2 mouse with a PIC microcontroller and some LED displays. Of course, this follows hot on the heels of using a PIC with a PS/2 keyboard so now might ...