For those who have had trouble or will have trouble in the future
getting gpm and X to cooperate, I have now published a short guide on
how to do it successfully. Enjoy.
http://dman13.dyndns.org/~dman/config_docs/gpm-X/
Kernel 2.6 extends this device node to include the PS/2 mouse as well.
This means that if you are using a 2.6 kernel you don't need to use
the gpm-as-repeater technique outlined above. Simply tell gpm to read
from /dev/input/mice and tell X to read from /dev/input/mice and it
will work correctly.