I've looked into Mogulus and have really liked what I've seen. You also might want to check out http://www.selfcast.com/.
Plus, if you want to do your own broadcasts the best application I have ever found that's done this is Wirecast, I "live and die" w/ this application using it on a daily basis w/ announcements for all of the districts I have worked in.
Check out an example of a video made in Wirecast. We edited the movie in iMovie but did the chroma-key, special effects, and broadcasting to the whole school in Wirecast.
We use it for one of our live streaming interactive distance learning GreenbushTV Channels @ http://tv.greenbush.us .... we are kind of transitioning to Ustrem.tv form most channels though - Ustream has come a ling way over the past 6 months or so!