kerio client

Ayttm - Universal Instant Messaging Client.

ICQ-like Jabber client designed to run in any Windows environment.

A secure IM client for XMPP/Jabber.

A multi-client internet messaging application.

FeyTorrents is a p2p client created for fast downloads and easy files managing.

Coccinella is a free and open-source cross-platform chat client.

Quassel IRC is a modern, distributed IRC client based on the Qt4 framework.

DexterWire is a fork of the very popular LimeWire Gnutella client.

Heighten the functionality of your Shareaza file sharing client.

A free add-on for the currently dominant BitTorrent client in the world.