Router & port forwarding

[Desert_Fox]

Hey,
Could someone please help me here is my problem:
I have two computers networked through a linksys router (wireless) and i know how to forward the port but im still not getting the server on one computer to be able to be casted from the other computer. I'm not sure how to do this and im not sure if it is the same ip so would i use localhost or not? any help is apreciated.