LAN-Messenger is an instant messenger that works on your home network. It allows you to communicate with other users on your home network without needing to be connected to the Internet. There is no need to install a server application, either. Any user with a Windows, Linux or Mac OS X computer can connect to the service and use any of the application's features.
From the application's main window you can start conversations with any other users running the utility, and you can also create new chatrooms, change your status, and start file transfers. Most of the features are accessible via the menubar. From there, you can also venture into the Preferences window. The look and feel of LAN Messenger can be tweaked here. There are 9 different Preferences categories: General, account, messages, history, alerts, network, file transfer, appearance and hotkeys.
When I first installed this utility I thought it was going to be rather simple and basic, but I was very wrong. It has support for file transfers, chatrooms, hotkeys, and even different alerts. Perhaps what I liked the most about this app is how easy it is to set up and operate. You can just pre-install this on all your computers and their users will immediately figure it out.