Finally Microsoft has released Silverlight 1.0 - Microsofts new streaming media platform which aims to compete with Adobe Flash.
Silverlight is a cross-platform and cross-browser plugin with focus on delivering high performing graphical web interfaces, with support for Windows and Mac OS. Download the final release here. The download page still says Silverlight 1.0 RC , but the RC will automatically update to the final version.
For Linux there is a project under the Mono umbrella called Moonlight which will provide a Linux implementation of Silverlight.
Full press release here.