Cameron Skinner blogged about this cool new vsix: It combines the reference architectures from Microsoft Patterns & Practices Application Architecture Guide with the new layered diagram features in Visual Studio 2010.
Just download the vsix from here and open it to install it to your Visual Studio 2010 RC. Then create a layered diagram in a new or existing solution, open the toolbox and there you have five new templates:
which you can just drag and drop to the design surface to create a fully AppArch compliant solution from scratch. In the above screenshot you can see the Rich Internet Application template, that I used. How cool is that. I expect a lot more extensions to the diagrams in the months to come.
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.