Matt Winkle introduced a sample solution called PageFlow which shows how to implement UI flow using the Windows Workflow Foundation. More details about the sample are at Matt's blog. Shelly Guo has a nice demo of PageFlow on Channel 9 here. I just watched it. PageFlow adds a new workflow type specifically for UI flow. In Shelly's demo, she shows using the same PageFlow for ASP.NET & WPF. Since introducing the sample, some recurring questions are being asked both internally and externally. Questions like "Why not a state machine?" and "What about WCSF / Acropolis / Codename 'foo'?" Matt answers these questions on his blog.