Check out the Silverlight 4 Training Kit to learn more about how to build
business applications with Silverlight 4, Visual Studio 2010 and WCF RIA
Services.
The training kit includes 8 modules, 25 videos, and several
hands-on labs that explain Silverlight 4 and WCF RIA Services concepts and
walks you through building an end-to-end application with them.
http://weblogs.asp.net/scottgu/archive/2010/04/22/silverlight-4-training-kit.aspx
The training kit is available for free and is a great way to
get started.