voice communication between two computers.

I have one computer, my wife's, upstairs, and my computer is downstairs. both computers have sound cards with micrphone inputs. I would like to be able to talk from downstairs and she hear me upstairs and vice-versa. Both computers are connected via TCP/IP network with NFS. I know this is possible with Windows, but both machines are Suse 8.0 Linux. Is this possible and if so, how would one go about it? Art