Last night, Josh Berkus did a great job of presenting the Postgres 9.2 features to SFPUG. The 75-minute video is now online. (The video is mis-titled as "July".) I also have a video of 9.2 features (registration required) that is more focussed on the 9.2 release notes.
I am planning to use Josh's slides at tonight's inaugural Philadelphia Postgres Users Group meeting.