First full trailer coming next week!
http://www.avpgalaxy.net/2012/03/07/new-prometheus-footage-to-premiere-at-wondercon-2012/
According to AMC Theatres website, the Q&A will last for 30 minutes and the footage shown at WonderCon will be the first full trailer for the film. The premiere will be invite-only but you will be able to watch the entire event live here. You may also submit your questions to Ridley Scott with the hash tag #amcprometheus on Twitter, or on the AMC Theatres Facebook page. The trailer will be avaible online shortly after the event.
http://www.avpgalaxy.net/2012/03/07/new-prometheus-footage-to-premiere-at-wondercon-2012/