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.
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.
PlanetaMessenger.org is a Instant Messenger with support to all well known instant messenger networks including ICQ,MSN,AIM,Yahoo! and Jabber through a powerfull plugin engine. PlanetaMessenger.org support multiples look and feels, plugins and profiles.
This is a crossplatform instant messenger. But now it's just ICQ client.
This is an Oscar Server for the AOL Instant Messenger client.