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 …

Empathy is a messaging program which supports text, voice, and video chat and file transfers over many different protocols. You can tell it about your accounts on all those services …

Imo instant messenger is a web-based service with video and voice chat functionality. imo's web messenger and mobile messenger apps let you IM your friends with AIM, Facebook, Google Talk, …

Chat everywhere! IM+ is the most widely used mobile IM app! Connect all-in-one to MSN, Yahoo!, Google Talk, AIM, Jabber, ICQ, Facebook, MySpace, Skype, and Twitter on ALL popular mobile …

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 …

eBuddy is a web and mobile messenger which supports various instant messaging services. Features include chat on Windows Live Messenger (also known as MSN), Yahoo! Messenger, AOL Instant Messenger, ICQ,...

The goal of Gajim is to provide a full featured and easy to use Jabber client. Gajim works nicely with GNOME, but does not require it to run. It is …

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 …

Galaxium is an instant messenger application designed for the GNOME desktop. It will allow you to connect to MSN, Jabber, and IRC. You can communicate with your family, friends and …

Zoho Chat is a web based chat system. You can access it using just a web browser and an internet connection. It does not need any software to be downloaded …

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 …

A beautiful, free, easy-to-use chat (instant messaging) application for the XMPP protocol (Jabber, Google Talk). Project has been discontinued, though source code is still available on website

Sim-IM is a multiple protocol instant messenger for MS Windows, GNU/Linux, FreeBSD. Sim-IM supports Jabber/XMPP, Google Talk, ICQ and AIM (Oscar), Yahoo! Messenger and Microsoft Messenger (MSN) protocols....

Portuguese messenger publish by SAPO. It has a sending SMS feature and the user can make audio-visual calls. GTalk can be integrated with this instant messaging program.