Shipped today: Silverlight 1.0, Expression Encoder 1.0 and Microsoft Silverlight 1.1 Alpha September Refresh
The shocking news is this announcement :

Microsoft Corp. today released to the Web (RTW) Silverlight™ 1.0, a cross-browser, cross-platform plug-in for delivering richer user experiences on the Web. In addition, Microsoft will work with Novell Inc. to deliver Silverlight support for Linux, called Moonlight, and based on the project started on mono-project.com.

http://www.microsoft.com/presspass/press/2007/sep07/09-04SilverlightPR.mspx
OMG! This is important, significant, major, big, huge! It means that we will be able to develop .NET apps that are truly cross-platform (Windows, Mac & Linux).
Scott Gutthrie's Blog:
http://weblogs.asp.net/scottgu/archive/2007/09/04/silverlight-1-0-released-and-silverlight-for-linux-announced.aspx

Over the last few months we've been working to enable Silverlight support on Linux, and today we are announcing a formal partnership with Novell to provide a great Silverlight implementation for Linux. Microsoft will be delivering Silverlight Media Codecs for Linux, and Novell will be building a 100% compatible Silverlight runtime implementation called "Moonlight".
Moonlight will run on all Linux distributions, and support FireFox, Konqueror, and Opera browsers. Moonlight will support both the JavaScript programming model available in Silverlight 1.0, as well as the full .NET programming model we will enable in Silverlight 1.1.

Miguel de Icaza's Blog:
http://tirania.org/blog/archive/2007/Sep-05.html

This is an historical collaboration between an open source project and Microsoft. They have collaborated with other folks on the server space (Xen, PHP and) but this is their first direct contribution to the open source desktop.
Microsoft benefits by making Silverlight reach the Linux and BSD spaces. We benefit by ensuring that users of open source operating systems get access to sites that adopt Silverlight to deliver content or spice up their web apps.
