Design Time Support for Data in Blend and Visual Studio 2010

Here are a few great articles on adding support for having sample data within Blend and Visual Studio 2010

http://karlshifflett.wordpress.com/2009/10/21/visual-studio-2010-beta2-sample-data-project-templates/

http://karlshifflett.wordpress.com/2009/10/28/ddesigninstance-ddesigndata-in-visual-studio-2010-beta2/

http://www.robfe.com/2009/12/the-curious-case-of-the-designdata-msbuild-target/