Microsoft's .NET & Connected Systems Evangelism team recently released all of the source code for their DinnerNow.net application.  If you're interested in learning .NET 3.0 technologies as well as the new 3.5 stuff coming out, this is a great application to run and explore.  James Conrad's team put together a great set of sample code that shows how "you can develop a connected application using several new Microsoft technologies, including: IIS7, ASP.NET Ajax Extensions, Linq, Windows Communication Foundation, Windows Workflow Foundation, Windows Presentation Foundation, Windows Powershell, and the .NET Compact Framework".

There's no better way to learn how these technologies can be used together than by walking through a real application and picking it apart.  In addition to the DinnerNow.net application, they've also released several labs that target VS.NET Orcas Beta 1 covering the following topics. 

• JSON with ASP.NET AJAX and WCF
• Developing Dynamic Data-Driven Websites
• Using DLinq (Linq to SQL) with the .Net 3.5
• Syndication using WCF
• Workflow Services using WCF
  

They'll also be releasing videos about the application.  I'll more than likely make some videos of my own that walk through the application as well in the near future.