Tim Sneath posted on his blog that the RC1 build for Silverlight 1.0 is available for download. Version 1.0 of Silverlight is targeted at web video and not as much at developers like the 1.1 release will be. Andy Plesser from Beet.TV has some more info and a chat with Sean Alexander about an MLB application that will be done in Silverlight.
In addition to releasing the RC1 bits for 1.0, they've released a 'refresh' of the Silverlight 1.1 alpha. There aren't a lot of significant changes with the alpha refresh, but Tim says it "includes the same core runtime as 1.0 RC1" which I'm assuming means it will be a bit more stable. I didn't see an official word on when Silverlight would be released, but I have to assume it's soon. Enough changed from the 1.0 beta to the RC1 that a lot of the samples are broken and I'd guess that Microsoft wants to give time to get those samples working in preparation for the final release.
Once it's released, it will be interesting to see what happens. Flash still has a gigantic head start and Flash 9 was the most quickly adopted version of Flash ever with 83.4% penetration in 9 months. Getting that kind of ubiquity isn't easy, so when Silverlight is finally released we'll all have to wait and see what Microsoft's strategy is. I also hope they release penetration numbers so we can find out how quickly it's being downloaded and how that growth rate compares to other runtimes. Congrats to the team on the RC1 build.