I've been tasked with putting together an online lecture series for early 2012 involving three different speakers from 3 different geographical locations. My audience will span strongly in one state in different cities, and then some pockets of attendees in other states and cities. The estimated online audience is 5,000. How do I put this together? I thought about using UStream for the broadcast, but how do I present the various speakers and their material? Would GoToMeeting help with this? My main problem is controlling for video/audio quality, and using UStream (or another service) to broadcast the presenters, and switch between the face of the speaker and their presentation material (powerpoint or similar). Any insight into this would be appreciated. I'm decidedly a novice.