Of course this is hardly news by now, but I wanted to take the opportunity to add my two cents on how some things fit together.
To begin with, you'll find everything you need to get started from http://www.microsoft.com/silverlight/overview/developers.aspx, including overviews from other perspectives if you feel included to view them. The quick links on http://msdn.microsoft.com/en-us/silverlight/default.aspx is also handy.
Because my blog has an XML spin to it these days, be sure to check out the XML Data topics for Silverlight. As you can see, XML can also flow to Silverlight applications - and with ubiquity comes additional value.
In terms of programmability, there are a number of APIs that are missing in Silverlight, improving download size and startup times for applications. There are some new classes as well, such as XmlXapResolver. This class makes it easier to work with XML deployed along in the same XAP package.
Finally, I couldn't possibly finish this post without pointing to the ADO.NET Data Services support in Silverlight. Just be aware that you should use the asynchronous version of the APIs to keep the UI from blocking on network requests, and it's the same client library you know and love.
All in all, the reach of your data just got a lot longer, with a familiar programming model, and you can now provide applications with a rich client experience that is straightforward to update and deploy. Time to change the world...