Bombyx - Bombyx is a graphical client for SILC (Secure Internet Live Conferencing). It is written in C++ and uses FLTK as the widget set, plus a few other libraries.
Chatterbox - Voice chat software, good for online training, seminars, or communities, including text, voice chat, co-browsing and application sharing.
Comms4free - Lists only freeware or ad-ware communications software, including text chat, voice chat, and video chat. Descriptions provided.
Irssi-SILC - Irssi-SILC is the original textmode client for SILC.
Lister Smart - A sleek and useful solution that is set to change the perception of SMS as a communication tool.
Milc - A SILC Client for Windows, Linux/*BSD, and Mac OS/X. Has integrated public/private key support, OS standards interface, and HTML rendered output.
Stealth Chat - Freeware program that includes strong encryption and stealth measures. Ideal for office workers.
Wander - By dragging the address or link in a browser to this software, you can publicly or privately talk to other users reading the same webpage.