I am currently working with Silverlight and Silverlight Streaming and had an issue over the weekend I am sure I will not be the last one to have so:

Don't try to load a Silverlight application from the file system, I mean double clicking an html file, prefer to have a little web application or even use "Starting ASP.NET Development Server from a right click in explorer" to test your application.

If you are a lucky MSDN Universal subscriber then you can get Expression Encoder (released yesterday with Silverlight 1.0) for free. How ?

Juts use the key you have for Expression Studio delivered on MSDN Subscriber Downloads, on the page Subscription Product Keys.

Jon made a great post about easier VPN usage.

Easier VPN connections from a Windows desktop - Jon Galloway

Silverlight is now available in final release 1.0, you might download it right now.

The bonus part is the application developed by my brother Mathieu for Discovery Channel shows up on the Silverlight website as one of the show case.