Rocky Lhotka has just released Beta 1 of CSLA .NET for Silverlight framework (and a corresponding version for Windows).
If you are unfamiliar with CSLA .NET, it is one of the most widely used business application development frameworks for the .NET platform. I expect it will be extremely widely used in Silverlight as well, since it provides even more direct benefits to Silverlight developers! CSLA .NET for Silverlight abstracts many of the complex issues faced when building business applications in Silverlight, and helps provide the same level of productivity and power developers are accustomed to on the .NET platform.
You can read an overview here:
http://www.lhotka.net/weblog/OverviewOfCSLANET36ForWindowsAndSilverlight.aspx
And you can find download links here: http://www.lhotka.net/weblog/CSLANET36ForWindowsAndForSilverlightBeta1Released.aspx
To my knowledge, CSLA .NET for Silverlight is the first major framework targeting Silverlight 2.0 to enter the beta phase, and Rocky expects to release the final version of CSLA .NET for Silverlight as Silverlight 2.0 itself is released.
And best of all, all the sample apps are in VB (as well as C#). And he's been primarily using VB in the demos when speaking about the framework, and the various issues he’s had to address in building such an ambitious project on Silverlight 2.0. (so all you folks wondering about the future of VB w/ CSLA can rest easy.)