Free network messaging software for windows

Instant Messaging System to create and control your own messaging network in a LAN or using Internet as transport.
Sonork is a private instant messaging system for Windows 95 and upwards.
It allows workgroups and companies to create and control their own private
Instant Messaging Network or use the client alone for Internet.
The client is freeware. Source codes available at the web site.
The client/server combination may be aquired after testing the free version which
has all the functionality of the retail version and does not expire. The free version
is limited to networks of up to 5 concurrent users.
For larger networks, very affordable licensing terms are available.

Net Message is a small tool to send messages across the network, using the Windows Messenger Service, so there is no client install required to receive the messages. Additional features include Message interception, history of sent and received messages, alias support and more. The program can also be started from the commandline to send bulk messages to recipients from a text file. What makes Net Message different from most other messengers is that it works on the full range of Windows products (Windows9x), it does not consume a lot of system resources. Also, Net Message supports sending of huge messages, such as long documents, by splitting them in multiple files, and joining them back together. Net Message detects where a received message came from, so you can easily reply to it.
Net message is very small and does not use any special runtime libraries, uses Win32 api.

A free, very small and very versitile instant message program for Windows Networking. Compatible with Winpopup and NT Message service, but much more powerful! Full keyboard control, tray-bar icon instead of polluting the taskbar, a (serverless!) contact list, URL recognizers and much more. THE ultimate message program for you Local Area Network!