There isn't really a lot of documentation on integrating PureMVC with Flex Modules so I thought I would post on these forums. (see attached for source)
The code that is included is based off Vic on Flex's Cairngorm + Modules example found here:
http://viconflex.blogspot.com/2007/05/can-cairngorm-and-modules-play-nice_12.html
This example is implemented using PureMVC and demonstrates how to use a "shell application" to load Modules that have been implemented using the PureMVC framework. It doesn't do anything fancy, but gives someone a good place to start when trying to dynamically link in PureMVC based modules into a Flex application.
The key to this example is that you can't reference the ApplicationFacade in the main application. I had issues trying to load an ApplicationFacade in the root app and then have each module load it's own ApplicationFacade or register Notifications to either facade. There is something interesting going on with the Singleton pattern and how the main application -> modules scope is being handled.
I am going to start working on a more elegant solution that allows cross-module notifications but for the time being, this should get people started on the road to using Modules built on the PureMVC framework.