I had a bit a free time last week to play around with silverlight.  A couple of observations based on my 2 hours of playtime are:

1.  Silverlight/XAML in general feel alot like Adobe FLEX 
2.  coding for silverlight won't make sense until you understand it is a CLIENT side technology so you will need to work with data connectivity just like you would with Javascript (making a AJAX call) or FLEX/FLASH making a call to a webservice.  So since silverlight runs on the client side it doesn't have access to a SQL datasource (for security reasons).....you'll need to reference a service (see notes and code below).

Getting Data into a grid.  Below is a little snippet from the codebehind of a xaml page. 

The process i went through was

1.  created a WCF service  library (don't forget about the clientaccesspolicy.xml..what a pain)
2.  Referenced Library in Silverlight project
3.  OnLoad call the webservice method that returns a collection (in my case) "GetIssuesAsync()"
4.  Add a method that captures the webservice methods "Complete" event

public Page() 

{    

   InitializeComponent(); 

   Loaded += new RoutedEventHandler(Page_Loaded); 

} 

void Page_Loaded(object sender, RoutedEventArgs e) 

{    

   ServiceReference1.Service1Client webservice = new Service1Client(); 

   webservice.GetIssuesCompleted += new EventHandler<GetIssuesCompletedEventArgs>(webservice_GetIssuesCompleted);

   webservice.GetIssuesAsync(); 

} 

public void webservice_GetIssuesCompleted(object sender, GetIssuesCompletedEventArgs e) 

{ 

    dataGrid1.ItemsSource = e.Result; 

}