Three new templates are available for Silverlight applications, both Silverlight Business Application and Silverlight Navigation Application. Furthermore style elements of these new themes are available to download, you can use them in any Silverlight applications. Finally these new themes include the new WCF RIA Services templates.
These three new templates are :
There are downloadable at this address, and these templates can easily be installed in Visual Studio 2010 :
And Expression Blend 4 :