Synergy lets you easily share a single mouse and keyboard
between multiple computers with different operating systems, without
special hardware. All you need is a LAN connection. It's intended
for users with multiple computers, where each system uses its own
display. It's a little like having a 2nd or a 3rd desktop.

The configuration file is /etc/synergy.conf. You will need to edit this
to suit your needs before synergy will work at all with the rc.synergys
script. Alternatively, you can choose to run synergys as a normal user, 
making your configuration file $HOME/.synergy.conf.