Computing/Conferencing

Video

 * MeBeam
 * Wengomeeting.com - free web-based videoconferencing
 * Red5 is an Open Source Flash Server written in Java that supports streaming Audio/Video (FLV and MP3)
 * Chat
 * videoconf

Phone

 * FreeConference - free web-scheduled conference call service
 * Lypp - free IM-initiated group calling (will launch in September 2007)

Chat

 * MIT Jabber Instant Messaging Service
 * Server (domain): mit.edu
 * Connect Server: jabber.mit.edu
 * Port Number: 5222
 * Username: your MIT Kerberos ID
 * Security: Use TLS Encryption, if possible

Miscellaneous

 * FreeSWITCH is an open source telephony platform designed to facilitate the creation of voice and chat driven products scaling from a soft-phone up to a soft-switch.
 * The EVO (Enabling Virtual Organizations) System