http://visualstudiomagazine.com/articles/2011/03/28/wcovb_webmatrix.aspx

Theme pack for Silverlight Business Application Released!! - @deepeshm - Site Home - MSDN Bl

Windows Application UI Development (Windows)

Silverlight 4 Windows7 Theme (Download details Silverlight 4 Application Themes)

Windows 7 Theme

http://visualstudiogallery.msdn.microsoft.com/2cee75f0-0bc2-4cb9-935a-2dde0fa3edf3/

Samples:

http://www.silverlight.net/content/samples/sl4/themes/windows7.html

http://www.silverlight.net/content/samples/sl4/themes/cosmopolitan.html

http://www.silverlight.net/content/samples/sl4/themes/accent.html

http://www.silverlight.net/content/samples/sl4/themes/jetpack.html