These whitepapers provide a good overview of Silverlight.

Getting Started with Silverlight
This article is a portal into the larger Silverlight documentation.

Silverlight Architecture Overview
This white paper provides a high-level overview of the Silverlight architecture and how it fits into the Microsoft offering for building next-generation Web applications. Also, this white paper provides an architectural review of the Silverlight technology.

Silverlight Overview
Provides an overview of Silverlight including a discussion on the differences between Silverlight 1.0 and Silverlight 2 Beta 1.

Breaking Changes in Silverlight 2
This topic discusses the changes made to the Silverlight runtime and Silverlight tools between the Microsoft Silverlight 1.1 Alpha September Refresh and the MIX 2008 release. The changes discussed in this article are focused on changes that might cause your older Silverlight-based applications to now fail or behave differently.

Using Silverlight and RSS with ASP.NET
Learn how to use Microsoft Silverlight and RSS through ASP.NET to create a simple hero bar that is easily customizable and regenerated.

These whitepapers provide an overview of the Video and Media capabilities of Silverlight.

Animation Overview
This article provides a high-level overview of Silverlight animations.

Audio and Video Overview
This article provide an overview of the Video and Media capabilities of Silverlight.

Using Silverlight to Build a Hero Bar
Learn how to use Microsoft Silverlight and RSS through ASP.NET to create a simple hero bar that is easily customizable and regenerated.

Silverlight and Web Analytics
Rich interactive applications and media players built using Microsoft Silverlight are easily integrated with web analytics services such as WebTrends On Demand, Omniture SiteCatalyst, Google Analytics, and Microsoft AdCenter Analytics.