It is very cool but there's a minor error where the package name is left off the screenshot (though the instructions are correct). One of the comments on the post noted that in order to use states with this approach you needed to make a small change from "mx.states"
I thought I'd post a version of this approach that included the states issue. I hilited where you need to change "mx" to "app" and where you need to add "app" as the namespace. The shots below are of code done in FlashDevelop 3 (beta 3).
UPDATE: September 14, 2007 1:07 PM I've had additional troubles with using the code-behind and states. I'm afraid for now it's best to hold off on using the approach.