The final version of Silverlight 1.0 and Silverlight 1.1 Alpha September Refresh have just been released to the web. They are available for download at

It's worth noting that Microsoft has established a formal partnership with Novell to provide a Silverlight implementation for Linux in the next few months.  Microsoft will be delivering Silverlight Media Codecs for Linux, and Novell will be building a 100% compatible Silverlight runtime implementation called "Moonlight". More detail at Scott's blog.