Pidgin

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...

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.

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.

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 …

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...

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.