Pidgin

Adium is a free and open source instant messaging application for Mac OS X, written using Mac OS Xs Cocoa API, released under the GNU GPL and developed by the …

Jitsi (previously SIP Communicator) is an audio/video and chat communicator that supports protocols such as SIP, XMPP/Jabber, AIM/ICQ, Windows Live, Yahoo! and many other useful features. Jitsi is...

Kopete is an instant messenger supporting AIM, ICQ, MSN, Yahoo, Jabber, IRC, Gadu-Gadu, Novell GroupWise Messenger, and more. It is designed to be a flexible and extensible multi-protocol system suitable …

Psi is an instant messaging application for Windows, Linux, and Mac OS X that connects to the free, open Jabber IM network (also known as XMPP). Localized versions of Psi …

emesene is a chat program that allows you to connect to different networks like MSN, Gtalk, Facebook chat, Jabber and others.

Traditionally, chat clients on the Mac have been anything but glamorous. Colloquy is an advanced IRC, SILC & ICB client which aims to fill this void. By adhering to Mac …

qutIM - free open-source multiprotocol ( ICQ, Jabber/ GTalk/Ya.Online/LiveJournal.com, Mail.Ru, IRC ) instant messenger for Windows, Linux, MacOS X, OS/2, Symbian, Maemo/MeeGo, Solaris and *BSD.

KVIrc is a free portable IRC client based on the excellent Qt GUI toolkit. KVirc is being written by Szymon Stefanek and the KVIrc Development Team with the contribution of …

Instantbird is an instant messaging client based on Mozilla XULRunner and the open source library libpurple created by the software developers of Pidgin. Instantbird is free software available under the …

Kadu is an open source Jabber/XMPP and Gadu-Gadu instant messenger client for Linux, *BSD, Mac and Windows.

Psi+ is a development branch of Psi IM XMPP/Jabber client. Psi is a cross-platform powerful XMPP/Jabber client (Qt, C++) designed for the Jabber power users.

WeeChat is a fast, light and extensible chat client. It runs on many platforms (including Linux, BSD and Mac OS). WeeChat is: - modular: a lightweight core with plugins around …

Spark is an Open Source, cross-platform IM client optimized for businesses and organizations. It features built-in support for group chat, telephony integration, and strong security. It also offers a great...

Tkabber is a Free and Open Source client for the Jabber instant messaging system. Its writen in Tcl/Tk, and works on many platforms (tested on Linux, FreeBSD, NetBSD, Solaris, MacOS …

Subway is a web-based IRC client with a multi-user backend and a JavaScript-heavy UI. Frontend/backend communication is done with websockets (or best available fallback where not available). The backend...

Crossplatform Jabber client. The core program is just a plugin loader - all functionality is made available via plugins. This enforces modularity and ensures well defined component interaction via interfaces.

OneTeam – simple, secure and easy to use. OneTeam is a versatile instant messaging client that is very intuitive to use. Even people who are new to instant messaging will …