The tutorials that are installed with SW are good at explaining this feature. I don't know of any books that are dedicated to sheet metal and SW.
The trick with SW and sheet metal is to make sure you have your "rough-in" part completed as much as possible before you insert Bends. I guess it's a pet peeve of mine. I hate getting models where a part has been Shelled, then Bends inserted, followed by Cuts and Extrudes, then Jogs and extra Flange feature here and there. Uck!
Not sure how much you have used SW, but just remember to Suppress your last Process Bends to get your flat pattern. If you perform a "rollback", then your model will not be available in other areas. "Happy the Hare at morning for she is ignorant to the Hunter's waking thoughts."
