Instant Messaging, Chat, and NetMeeting

ICQ
http://web.icq.com/
ICQ 2000b is the latest release of ICQ ("I seek you"), the popular instant-messaging program that lets you communicate with friends and colleagues in real time. To seek out a friend on the ICQ network, simply enter his or her ICQ number, name, nickname, or e-mail address.

Yahoo Messenger
http://www.zdnet.com/downloads/stories/info/0,10615,46131,.html
Yahoo Messenger (formerly known as Yahoo Pager) is a free service that allows you to see when friends come online and send them instant messages. The newest version of Yahoo Messenger adds Webcam capabilities. Using a Webcam, you can see who you are chatting with, or view the Webcam of any Yahoo member who has granted you access.

Odigo
http://www.zdnet.com/downloads/stories/ info/0,10615,48323,00.html
Odigo is a cross-platform instant messenger that allows users to connect with users of ICQ, and AOL and Yahoo messengers. (It takes only a minute to import your buddy list from AIM, Yahoo Messenger, or ICQ.)

Microsoft NetMeeting
http://www.zdnet.com/downloads/stories/info/0,10615,17269,.html
Microsoft's NetMeeting integrates audio, data, and videoconferencing into one package. Its data-conferencing features let you draw on a shared whiteboard, send text messages, transfer files, and collaborate in real time with multiple people within any Windows application. NetMeeting's real-time audio features let you talk to other people over the Internet.