Pidgin - Pidgin is an easy to use and free chat client used by millions. Connect to AIM, MSN, Yahoo, and more chat networks all at once.
LAN Messenger - LAN Messenger is a decentralized UDP IM-style chat client which supports usernames...
Jitsi - Open-source video calling and chat platform.
MyChat - Secure instant messenger for any network
Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.
BORGChat - BORGChat is a LAN messaging software program.