Google Hangout has been a coll feature where people can do video conferencing for free and it is totally web based. I have been a regular listener of AstronomyCast who were recording their episode 236 live in a Google hangout session on 24th October 2011. It was great to be in the live recording session with Pamela Gay and Fraser Cain along with other people having interest in astronomy. The interaction session before and Q&A session after the recording was great. Here is a clip I had recorded during the session.
The topic of this episode was "Einstein was right" . Pamela and Fraser cited many evidences which tells us how accurate the predictions made by Einstein's general and special theory of relativity were You can download the podcast mp3 here or listen in the following player. if you want to join the next recording session , you can Circle Pamela or Fraser so that they can invite you the hangout session.