I have created a simple unwind segue using the storyboard tools. I have created the following event handler in the view I want to unwind to:
-(IBAction)quitQ
Getting data back from an unwind segue is explained very nicely in this apple talk, second half of the presentation (edit: starts from 37:20)
In particular, in an unwind segue the [segue sourceViewController] is the still active view controller from which the unwind event originated, so just access your properties as usual.