I came across a helpful article from Omnipress. It highlights different avenues for using video to raise awareness about your conference and build event attendance.
CFMA Conference 2009 Las Vegas
Promotional video to promote upcoming event.
The American Physical Therapy Association
Showcasing many great reasons to join APTA
American Watercraft Association West Coast Freedom Ride 2008
Captures their event in a slide show like video format.
2008 National Association of Realtors Convention in Orlando, Florida
Interviews direct from the convention floor. Great way to capture the experience
Here is a link to the full article. http://blog.omnipress.com/2009/01/5-ways-associations-are-using-video/