MIX09 Las Vegas unveiled Silverlight 3 Beta with new enhanced media feature, Improving RIA Productivity, Advanced Accessibility Feature and Out-of-Browser Support.
Check out the detail here:
http://blogs.msdn.com/silverlight_sdk/archive/2009/03/18/silverlight-3-beta-released.aspx
Download Beta and Get Started here:
http://silverlight.net/getstarted/silverlight3/default.aspx