I've talked about Zend Framework's action helpers before, but haven't covered any of the action helpers that are supplied with Zend Framework. FlashMessenger is a helper that allows you to store messages between requests. The most common use I have for it is for a "saved" message after doing an edit of an item that then redirects back to a list.
He includes an example of this helper in action in storing a sample message and pulling it back out on the other side. The message insert also includes a redirect() call and the output has a code snippet to check the messages property to see if there's any to show.