Dean,

once there is no server issues all you need to do is get a hub ,three cables and attach each computer to the hub. Make sure that the workgroup on each pc is the same, right click on network neighbourhood-properties-netword id. then restart each pc and they should see each other in the network. if you have to set up a server with a domain then it is slightly more tricky, although the hardware setup is still the same the software take a bit more.

Cheers
~M