Rolesoft Messenger 

Rolesoft Messenger Server and Rolesoft Messenger Client.
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Secure Network Messenger 

Secure Network Messenger (SNM) - is a real time network communication program able to send and receive messages and files from one computer to another without using dedicated servers
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QuickMessenger 

QuickMessenger is a simple tool that provides an enhanced interface for Instant Messenging and allows you to send text messages from one computer to the other or to a group of computers (on the LAN).
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ENat Offline for MSN Messenger 

ENat Offline for MSN Messenger enable you to send a message to your friend even if he is offline. Offline messages will be delieved to your friends immediatelly when he signs in next time. The add-on is fully integrated into MSN Messenger.
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Cell Messenger 

Cell Messenger lets you send, receive and archive SMS messages from your mobile phone. It provides support for reading your mobile's phonebook, sending group messages, anti-spam SMS filtering, unicode and multipart SMS messages.
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LanToucher Instant Messenger 

LanToucher Instant Messenger is instant messaging software for your office or home LAN (Local Area Network) True serverless (peer-to-peer) messaging; Proven cross-platform compatibility; No dedicated server or Internet connection is required.
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