command line example cause it is so quick and simple
On computer A
sudo ip ad add 10.0.0.10/24 dev eth0
On computer B
sudo ip ad add 10.0.0.20/24 dev eth0
To test from A to B
ping 10.0.0.20
To test from B to A
ping 10.0.0.10
/code>
Reference: http://askubuntu.com/questions/22835/how-to-network-two-ubuntu-computers-using-ethernet-without-a-router
If Win involved: http://helpdeskgeek.com/networking/connect-two-computers-using-a-crossover-cable/