http://www.freejavachat.com/
Here, you can get a free, customized chat room for your Web site. FreeJavaChat.com offers Java-based chat rooms that include a feature-rich IRC-compliant Web interface. A big plus for this service is that it displays no ads.
http://www.cybernetworlds.com/
Immerse yourself in the fascinating world of 3D chat with CyberNet Worlds' free 3D chat browser. Here, you can roam around various colorful 3D landscapes, chatting with users from around the world and build your own virtual home. The CyberNet community also stages social events, parties and contests. (For Windows).
http://www.ceruleanstudios.com/downloads/
Are you tired of having an instant messaging program that always seems to be incompatible with the ones your friends use? Trillian Basic is an outstanding freeware program that allows you to access any of the Web's five major instant-messaging services: AIM, ICQ, MSN Messenger, Yahoo! Messenger and IRC. This new version adds useful features such as 128-bit encryption and group chat. It's free for non-commercial use. (For Windows).
http://www.microsoft.com/windows/netmeeting/
With this cool program, you can hold virtual meetings. NetMeeting offers various tools to communicate and collaborate with others on the Web. It lets you hold voice and video conferences, share software applications, chat, and share a whiteboard.
http://www.icq.com/download/
A must-have instant messaging and chat program from Israel that ranks as one of the Web's most useful freeware programs. ICQ's features could fill a book but the most important innovation it offers is "awareness" (the ability to determine whether other people are online at a given moment). Available for Windows, Macs and Palms.
http://www.activeworlds.com/
We think that this is one of the coolest freeware programs on the Web. It's a browser that lets you access AlphaWorld, a unique, 3D virtual community populated by real people. The Active Worlds universe boasts thousands of users who you can chat with. You can explore over 100 worlds in real-time, high-color graphics. You can even own land and create buildings on your property, from a simple house to an elaborate palace (a process that is quite easy). (Available for Windows, Macs and Linux).
http://www.aim.com/
This popular program, once available only to AOL users, is now available to the entire online community. It offers many cool features. It allows you to see who's currently online (like ICQ) and lets you send quick and private instant messages, as well as pictures. You can also communicate via voice, (provided you have a microphone and speakers). (Available for both Windows and Macs).