About the 2 flash video chat applications:
AVChat 2.0 is a flash video chat software to be used by web sites with lots of users. It comes packed with lots of features including private messages, audio video support, rooms support an admin section with kick and ban, etc... .
AVConference is a flash video chat software to be used in conference scenarios and the like. It has many features ( audio video support, users list, rich text chat, file sharing, a moderator section, etc...) and it also provides support for the free Flash Media Encoder for better quality video.
Both apps run in the browser like any other flash app, and they use Flash Media Server to stream audio and video from one user to another. Both apps are commercial. Recently we have wrapped them into Drupal modules (Drupal 4.7.x and 5.x for now, the other versions can be supported at request).
About the 2 Drupal modules: