ScottGu just announced the Silverlight 1.0 Release on his blog for Windows and MAC. Silverlight 1.0 is focused on enabling rich media scenarios in a browser. Head over to this blog for more info on this and to see some deployed Silverlight 1.0 examples.
I already jumped on the Silverlight 1.1 train as it features full .NET Language support. The good news are that the MS Silverlight team can completly focus themselves on the v1.1 Release now.