Hey Mark,
To Convert Applications to modules means changing the base class of your main application from FlexModule to FlexApplication. The shell application would load the FlexModules with the FlexModuleLoader.
var moduleLoader:FlexModuleLoader = new FlexModuleLoader();
moduleLoader.url = "moduleX.swf";
moduleLoader.router = applicationRouter;
addChild(moduleLoader);
For sending messages between the modules you can use the routeNotification method available throughout Fabrication's commands, mediators, etc. If your modules are called ModuleX and ModuleY. You can send messages to and from using routeNotification as,
// module X to Y
routeNotification("myNote", myBody, "myType", "ModuleX/*");
// module Y to X
routeNotification("myNote", myBody, "myType", "ModuleY/*");
// shell to both X or Y
routeNotification("myNote", myBody, "myType", "*");
There are some other considerations when switching between applications to modules if you are using Flex 3.2+ to do with the
Marshall plan. This mostly to do with how you subscribe to system events and such.
I suggest taking a look at the
Example applications like simple_routing. Hope that helps.
peace,
darshan