This will also be an interesting project to link inro dotWRK http://openacs.org/forums/forum-view?forum_id=14014
Also the recent event in Copenhagen where Mohan did the live blogging an extension like this would have been great as the event was put on video aswell.
I'm as well interested in what you have in mind there. We talked a lot about CMS during the OpenACS social and treating streaming data as one asset would be a huge benefit as well. That is, if you are talking about embedded streaming within the browser.
Otherwise I can imagine using streaming media as one other type of content like files and html pages that could be categorized and linked with the streaming server.
About Icecast is just a audio streaming server, 1.3.x is for MP3 (not supported anymore) and 2.x are of Ogg Vorbis.