1)   Outlook LAN Messenger 5.0.0
Instant messaging software designed for use within Small and Corporate Office's Local Area Network. Features include Text & Group Chat, Voice Chat, File Transfer, Offline Messaging. Its Server-less, requires No internet connection & Easy to install.

 2)   Bopup Messenger 5.3.6.6001
This clear, easy to use and light-weight IM client offers a set of corporate features. Based on a client/server architecture the messenger is fully managed from server-side software which provides IM logging, user grouping, offline messaging.

 3)   VSL LanToucher Network Messenger 1.15
LanToucher is a full-featured, Microsoft WinPopup-compatible LAN messenger for Microsoft Windows 95/98/NT4/2000/ME/XP/Server 2003. Designed as a WinPopup and "net send" replacement, LanToucher provides many more functions, options and features.