I have been trying to find a good answer for you but I keep finding that a server seems to be involved.
In windows xp there was a program called netsh. I believe it would work like you want.Win 7 and 8 replaced it with a program called msg. It does not seem to work quite the same. If you were running Linux on your computers than a command called talk would be an excellent choice. There is an article on installing an irc server directly on your node on the website. I am not sure if it still fits on a wrt54g or not. II would recommend putting a server on one of your pc's. Do a google search on windows chat server freeware. You will find instructions and videos on how to set one up |