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.
Psi+ Project — development branch of Psi XMPP client
Psi is a cross-platform powerful XMPP client designed for experienced users. Psi+ is a development branch of Psi XMPP client. Project purpose: collection, refinement and writing new patches for transfer them to Psi upstream developers.
A multi-protocol instant messaging app for Mac OS X
Adium is an Open Source, multi-protocol instant messaging application for Mac OS X. Adium supports AIM, ICQ, Jabber, MSN, Yahoo!, Google Talk, Bonjour, Gadu-Gadu, Novell Groupwise, SIP/SIMPLE (Text), and Lotus Sametime. Additionally, it supports all of these applications at once so, even if you have multiple IM accounts, you don't have to log into each account separately.
ExtremeTalk(XT)是一个用于企业或者组织内部进行在线通讯的，基于XMPP(Jabber)协议的即时通讯系统。ExtremeTalk(XT) is an Instant Messaging(IM) collaboration platform based on XMPP(Jabber) for enterprises and organizations
OfficeTalk is an instant messaging collaboration platform for enterprise, organization. ExtremeTalk是一个适用于各种规模的企业，单位和组织的即时通讯方式的协作平台
an universal internet messenger client tool using XMPP. it is able to communicate with any messenger like msn, yahoo, aol, google talk, etc. this application is developed in java, and is able to run on any environment.
imEcourse is a course electing system for college students.It bases on IM.Including executable application IM and web-IM. To use IM to elect course?Of course!
nebohodimo IM is a Jabber client for Windows Mobile devices. It's written to be stable over unreliable mobile connection and easy to use.