Microsoft has released Silverlight 1.0 to the web today, and announced that they have partnered with Novell to build the Linux implementation of Silverlight, called Moonlight. That means that Silverlight now has support on all 3 major OS platforms
The bits aren't available at the moment, but I'm sure they will be soon.
[via G. Andrew Duthie]
UPDATE: Microsoft's Scott Guthrie has, as always, posted an extremely in-depth update on what is going on in the world of Silverlight. It's a must-read if you aren't up to speed on what Silverlight is, or why it is important.