Today I happened across a fantastic site that provides a comprehensive list of annotated links related to Conferencing on the Web. The information here is very current, including a link to beta software from Adobe.
Adobe AtmosphereTM looks very promising. I'm especially intrigued by the avatars -- animated characters which represent users in online environments.
The fact that Adobe is providing a community server during BETA phase of their rollout is also a good thing. The cynic in me says that you'd better get busy if you want to take advantage of the community server -- these "freebies" have a recurring habit of going away.