Microsoft Silverlight, the technology formerly known as WPF/E, is a cross-browser, cross-platform plug-in for delivering the next generation of media experiences and rich interactive applications (RIAs) for the Web. Silverlight seamlessly integrates with existing Web applications and supports fast, cost-effective delivery of high-quality audio and video to all major browsers running on the Mac or Windows. 

 

There are some downloadable bits available now for you to try out today - here are a couple of links to get you started: