Scott Guthrie has a great eight part series titled First Look at Silverlight 2 where he walks you through building a Silverlight 2 sample app from scratch.  The walkthrough highlights almost all of the key features of Silverlight 2 Beta 1.  The walkthrough is so comprehensive that I have been using a slightly modified version of it for my Silverlight 2 presentations.  Since I am a big fan of seeing vs. reading, I asked Scott if it would be ok if I turned his written walkthrough into a video walkthrough delivered as a Channel 9 screencast.  Scott gave me the thumbs up so I put together what turned out to be a three part screencast.  Here are the direct links for each part:

Silverlight 2 DIGG Sample Part I

Silverlight 2 DIGG Sample Part II

Silverlight 2 DIGG Sample Part III

I hope you find it useful!  The source code for the app is available at http://cid-1f72da7294089597.skydrive.live.com/self.aspx/Public/Silverlight%202/MyDiggSample_Silverlight2Beta1.zip.