Open the GoXam Introduction for a getting started guide.
API Reference Manuals
And for even more detail, here are the API Reference manuals.
Video Series VS2010 - Building a Silverlight Business Application
Video 1: Building an OrgChart with RIA services and Silverlight 4 / VS2010 YouTube
Video 2: Enhancing appearance using gradients and shadows YouTube
Video - VS2008
Building an OrgChart with RIA services and Silverlight 3 / VS2008> YouTube