Came across this very good paper on Microsoft .NET RIA Services.
“.NET RIA Services address the complexity of building n-tier applications through framework, tools and services. Framework components support prescriptive patterns for writing application logic and validation so that it can be easily used on the presentation tier. Tools add to existing Visual Studio capabilities by linking the client and mid-tier projects in a single solution and by enabling smart code generation in client projects. Accompanying services utilize the prescriptive pattern to support commonly used capabilities such as authentication and user settings management.”