Conferencing

Audio Conferencing

Free Phone
 Free  - An audio tool for the Internet supports multiple concurrent unicast and multicast conversations

RAT (Robust Audio Tool)
An open-source audio Free conferencing and streaming application that allows users to particpate in audio conferences over the Internet

Speak Freely
An Open Source Internet Telephony USA Release for Windows 95/98/NT/2000/ME

VOIP Telephony

CyberPhone
Internet Phone for MS Messenger and VOIP telephony service provider

Callserve  
VOIP Telephony service provider, charge in UK£ 

iConnecthere.com
VOIP Telephony service provider, charge in USD

go2call.com
VOIP Telephony service provider, charge in USD

Skype Advanced VoIP Telephony

Video Conferencing

WebEx MeetMeNow – Online Meetings - 14-day free trial; easy web meetings

Dwyco Video Conferencing System (CDC32)
Adware or register for no adverts

Marratech
Marratech Pro - Free Client software communicates with Marratech E-meeting Server Portal

Microsoft NetMeeting
 Free  Video conferencing client

VIC
Video Conferencing Tool by the Network Research Group at the Lawrence Berkeley National Laboratory in collaboration with the University of California. Video Conferencing Tool by the Network Research Group at the Lawrence Berkeley National Laboratory in collaboration with the University of California. Free  Source code and pre-compiled binaries

Instant Messaging

CGI Resource Index
Perl script for Instant Messaging

Instant messaging:
How to plug its holes in your security
Internet Security

Jabber Software Foundation
Jabber is an open, XML-based protocol for instant messaging and presence. Jabber-based software is deployed on thousands of servers across the internet and is used by over a million people worldwide.The protocol itself is managed by the Jabber Software Foundation.

Trillian by Cerulean Studios
 Free  - Trillian is everything you need for instant messaging - connect to ICQ®, AOL Instant Messenger(SM), MSN Messenger, Yahoo! Messenger and IRC in a single, sleek and slim interface

vypress.com
Instant messaging and alerting software Vypress Messenger & Vypress Chat WinMessenger - an easy to use program that allows you to send and receive messages from computer to computer in real-time without using dedicated servers

Instant Messaging Portal

AOL
 Free  Messaging client AIM

ICQ.com
 Free  ICQ

Google Talk

iMessenger

MSN® Messenger
 Free  Messenger

Yahoo Messenger
 Free  Messenger

IRC (Internet Relay Chat)

Chatting on the Net
IRC general guides

IRC Help Archive
The most complete IRC help site: over a thousand helpful files incl. FAQs, primers, guides, downloadable clients & scripts and server list etc.

IRC.org
Information about IRC: History Links Server & Client software ..…

IRC Client Software

Cnet Download
Search for 'IRC Client' found 58

Tucows
Search for 'IRC Client' produced a list of 300+

IRC Server Networks

AustNet - A global network
Server List

DALnet
Server List

Eris Free Network
Server List

EsperNet Servers
North America - Europe - Australia

GalaxyNet
North America - Europe - Middle East - Asia - Oceania

IRC Server List - Moonbeam.co.za
A comprehensive server list

IRC Servers Network - Undernet.org
One of the largest realtime chat networks in the world with approximately 45 servers connecting over 35 countries

OPN Open Projects Net
Provides an interactive environment for free software and open source projects and support groups with over 5,500 users and 2,100 channels

oz.org
The Australian Internet Relay Chat Network

Sorcery.net

StarChat
Server List

StarLink IRC Network
Channel List

WebChat
Server Index

Xnet