I’ve just started using CoffeeScript with JQuery and Rails and I needed some system to organize my code. I’ve put all my classes and global variables in an app namespace, lets call it MyApp and for each controller I have a class and within that I have static methods for each action that is only run when that action is run.
You can package Actionscript classes into a SWC files – they are equivalent to JAR files in Java. You then reference the SWC file from your FLA. You might want to do this if you come up against the memory limit in the Flash compiler, or you might want to distribute libraries without distributing the source code. It also speeds up compiling because you are including pre-compiled code. The following instructions are for CS4 but it works in CS3 also.