The idea to provide a streaming service of free content is – apparently – not a new one. Apart from the old WikiCast project, Creative Commons have been looking into starting something up. They’re further along than Wikimedia and in a position to run –NC material.
A mailing list for discussion has been set up here, http://www.open-mesh.se/cgi-bin/mailman/listinfo/justfm/
The discussion on meta is at http://meta.wikimedia.org/wiki/WM:RADIO