Microsoft has released a Beta of Silverlight, a cross-platform plugin similar to Flash which allows you to view Silverlight web-based rich media in your browser, whether Internet Explorer or Firefox, on a Mac or PC. Once you install Silverlight, you can see a demonstration of its capabilities by viewing the movie previews on here : http://silverlight.net/fox/

Download Silverlight now : http://www.microsoft.com/silverlight/downloads.aspx

*credits goes to http://tweakguides.com/

Looks good, but I wonder if it'll actually take off. Also wondering how hard would it be to develop