Call it layered of n-tier also can, Serena Yeoh aka Firedancer who now works in Microsoft Consulting Services came out with a sample application based on the whitepaper – Application Architecture for .NET: Designing Applications and Services.
It is hosted at Codeplex and now at its 4th release. Besides demo how to built enterprise level application using .NET, it also features new cutting edge .NET 3.5 technologies such as LINQ, WPF, WCF and WF. By basing on the best practices of the MSDN Architecture whitepaper, this Expense Sample app also showcase and helps you to jumpstart SOA and S+S based architecture.
Again, here is the link
