This mini-HOWTO was created by gathering the information already available on the internet, in newsgroups and other HOWTOs. I needed to hook up an USB mouse in addition to the built-in trackpoint on my Thinkpad laptop.
Examples in this mini-HOWTO pertain to my particular hardware configuration, which is PS/2 mouse as a primary pointer and USB wheel mouse as an additional one. It should be pretty straightforward to implement another combination, say, a PS/2 and a serial mice. Two things that would have to be changed are the mouse protocol and the mouse device. Wherever possible, I try to provide appropriate examle.
The instructions for X are divided into two sections, one fro XFree version 3 and one for XFree 4. The format of the XF86Config file has significantly changed between versions and requires slightly different approach. In XFree 3.x, the second mouse has to appear in an Xinput section, which has slightly different syntax than the regular Pointer section. In XFree 4.x, it's just another pointer.