There isn't as yet a comprehensive how to, but there are two presentations at
http://puremvc.tvStateMachine Utility Overview
http://puremvc.tv/#P003/and
Getting in the Groove with PureMVC
http://puremvc.tv/#P004/The second one talks about the statemachine that is implemented in the Sea of Arrows player site at
http://seaofarrows.comYou can read the source code at
http://seaofarrows.com/srcview -=Cliff>