I have been experimenting with both Open Meetings and DimDim to deliver live instruction and video/audio communications for our eLearning Platform. I really like the dimdim VMWare install, but they currently do not allow recording of meetings. Just the other day I gave open meetings a shot and got it running on my local machine. I was impressed with the system. It seemed to work well for simple on the fly video communication. You can have up to 20 people watch a presenter as well.
Hopefully I will be able to have this running shortly. I will try to post a screencast with it running.