As Vittorio Bertocci and Paul Andrew mentioned, the first case study for Windows Workflow Foundation is now available on Microsoft.com here.  The case study describes how Polfer (Italian Railway Police) developed a document management solution using WF and SharePoint 2003.   Vittorio worked with Polfer and the MCS Italian team on this project.   This will be the first of many case studies on WF and the .NET Framework 3.0.