Ars Technica reports on the 3.1 Alpha of Firefox, which includes support for the HTML 5 Video element which provides some functionality to developers that is not possible with Flash. Video can be interspersed with other web content, playback can be manipulated with JavaScript, and video elements can be directly accessed through the document object model.
Bluish Coder demonstrates the Video tag in SVG to implement a Silverlight style demo in Firefox 3.1 alpha. The demo shows transparent layers of videos that can be dragged, moved, and resized.
http://arstechnica.com/news.ars/post/20080905-first-look-firefox-3-1-alpha-2-officially-released.html