Clients

Akeni
A client that provides a familiar, MSN Messenger like, interface to Jabber communications.
http://www.akeni.com/product/jabber.php

BuddySpace
Open source Jabber-based instant messenger written in Java that adds customisable graphical metaphors for presence.
http://projects.kmi.open.ac.uk/buddyspace/

Centova Instant Messenger
Full-featured, cross-platform instant messaging client which requires no software installation, running entirely from a web browser.
http://www.centova.com/pages/msgrdetails/

Chatopus
Jabber/XMPP client on Palm OS platform. Supports transports and real-time news via RSS feeds.
http://www.chatopus.com/

Coccinella
A client with whiteboard communication. Windows, Mac and Unix/Linux support.
http://coccinella.im/

Enigma Squared
Java2 compliant client featuring plugins and focusing on user friendliness and ease-to-use.
http://complat.sourceforge.net/

Exodus
A client that is developed as a successor to winjab, it aims to be a end user client with a smaller interface.
http://code.google.com/p/exodus/

Freetalk
Freetalk is an extensible console client.
http://www.nongnu.org/freetalk/

Gabber
A robust and premiere GNOME Jabber client. Written in C++ using GTK+, Gnome and the Jabberoo C++ Jabber client library.
http://gabber.sourceforge.net/

Hackamore Jabber Client
Hackamore is a client written with FLTK Gui Toolkit with C++.
http://hackamore.jabberstudio.org/

imov Messenger
A Windows CE client for the Jabber instant messaging system.
http://www.movsoftware.com/products/imov/imov.htm

Jabber Web Chat
A web-based client written using AJAX technology. It supports basic jabber instant messaging, roster management and groupchats based on the MUC protocol.
http://jwchat.org/

JabberBeans
Standalone Java client application and applet which aims to create a base layer for applications to be "Jabberised" quickly and easily.
http://jabberbeans.sourceforge.net/

JabberFoX
A client for Mac OS X. An open source instant messaging system fully based on XML.
http://jabberfox.sourceforge.net/

Jabbernaut
A Macintosh client based on MacJLib.
http://jabbernaut.sourceforge.net

JabberPalm
Am open source client for the Palm platform, not maintained since 2001.
http://sourceforge.net/projects/jabberpalm

Jabberwocky
Presentation of an open source client for Amiga computers with FAQ and download.
http://jabberwocky.amigaworld.de/

JabberX
A console-mode client for the Jabber platform. (GNU license)
http://jabberx.jabberstudio.org/

Jabberzilla
Client plug-in for Mozilla, written with XUL and Javascript languages.
http://jabberzilla.mozdev.org/

Jarl
Jarl is a Perl/Tk feature-packed, cross-platform client that runs on all major platforms.
http://jarl.sourceforge.net/

JeweL
Client written with Perl/GTK+ using the Net::Jabber perl modules.
http://jewel.sourceforge.net/

Lluna
Client for windows that integrates with Internet Explorer and allows to chat with other people that are browsing the same page.
http://www.lluna.de/

mJabber
Instant messaging client for mobile phones, PDAs or other wireless devices.
http://www.mjabber.com/

neosmt
Multi-protocol IM client with Jabber, VoIP, digital whiteboard and file transfer support.
http://www.neosmt.com

NewtJab
A client for the Apple Newton.
http://newton.guhl.net/newton/newtjabber/

Pandion
Client designed for usability, standards compliance and security, including automatic connection encryption, custom emoticons, avatars and text markup.
http://www.pandion.be

Psi Jabber Client
Psi is a multi platform client currently available for Windows, Linux and Mac. It mimics the looks of Licq.
http://psi-im.org

QTJim Project
Cute client using the QT toolkit. Freely available, licensed under the GPL.
http://www.telecom.tuc.gr/~perak/utils/qtjim/

Smack API
XMPP client library for Java.
http://www.jivesoftware.org/smack/

Spark IM Client
Free, secure, cross-platform XMPP client with built-in group chat, telephony integration and tabbed conversations.
http://www.jivesoftware.org/spark/

Tkabber
A client written in TCL, it supports JEP-38 style Jabber icon-sets.
http://tkabber.jabber.ru/

Ultimate Jabber Client
Client with many features made for users who are new to the Jabber community.
http://ujc.pytalhost.de

Web Jabber
Web-based open source client written in Java.
http://www.webjabber.net

WinJab
Windows client that is under the GPL.
http://winjab.sourceforge.net/

Yabber
Windows IM application based on the Jabber protocol.
http://www.yabber.org/