Windows Workflow Foundation is one the coolest thing that i see in years , its prrety much in news and hype is quite massive (http://msdn.microsoft.com/windowsvista/building/workflow/) . Well I start playing with it and as it is in beta1 it still behaves quite fine accept few hitches . I also develop a custom Activitie which you can find at http://www.windowsworkflow.net/ControlGallery/ControlDetail.aspx?Control=2229&tabindex=2 .
Well gona update on this in the future ! .