State Machine Workflows

http://www.codeproject.com/KB/WF/JumpStartMF.aspx

http://msdn.microsoft.com/en-us/library/ms734766(v=VS.90).aspx

http://visualstudiogallery.msdn.microsoft.com/en-us/7fe6f504-a58d-456e-8f55-e64bddc81a41