A universal instant messaging (IM) program
See https://pidgin.im/about/ for more information. Pidgin is an instant messaging program which lets you log in to accounts on multiple chat networks simultaneously. It runs on Windows, Linux, and other UNIX operating systems. Pidgin is compatible with the following chat networks out of the box: AIM, ICQ, Google Talk, Jabber/XMPP, MSN Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, MXit, Novell GroupWise Messenger, Lotus Sametime, SILC, SIMPLE, MySpaceIM, and Zephyr. It is written in C and makes heavy use of GLib and GTK+. Finch is a command line instant messaging program. It also lets you log in to accounts on multiple chat network simultaneously, and it is compatible with the same chat networks as Pidgin. It is written in C and makes heavy use of GLib and ncurses.
MSN compatible messenger application
A very nice MSN compatible messenger application, aMSN Messenger is a multiplatform MSN messenger clone. Works pretty much like its Windows based counterpart. Perfect for keeping in touch with those friends who have not yet seen the light. Works on linux
Bot Sentry is a Pidgin (libpurple) plugin to prevent Instant Message (IM) spam. It allows you to ignore IMs unless the sender is in your Buddy List, the sender is in your Allow List, or the sender correctly answers a question you have predefined.
A fork of pidgin which aims to provide minor features that have not been addressed by the pidgin development team (including manual textbox resizing). See funpidgin.sf.net for details.
Scribis is an instant messenger for the ICQ, MSN, Jabber Network. Scribis runs on SkyOS (www.skyos.org) and uses its native UI called SkyGI.
Gaim Python plug-in. The product provides developers with the capability to develop python plugins for Gaim.
Open Source Community Software. With this software you can create profiles, chat with other people, visit other peoples profiles, create your own picture galery's, and later your friends will be able to watch them.