I know the source for the framework has been out for a while, but if you have not done this yet...DO IT! Trust me. You need the code, you need to browse the code, and you need to set breakpoints.

I saw the steps done at the last 360 Flex conference...but who knows where that notebook or braincell went. Anyway, I figured it out quickly, here are the steps:

1. Checkout the current version of the framework from here: http://opensource.adobe.com/svn/opensource/flex/sdk /tags/3.0.0.477/frameworks/projects/framework/
   Make sure that exact directory gets added as a project. I called my project flex_framework.
2. Add a Flex Library Nature to the project
3. In the Build path in the flex_framework project properties set the "Main src folder" to "src"
4. Then in the same screen check off just the class FrameWorkClasses to be included in the library
5. Then you add this project to your current projects library path In project->properties->Flex Build Path->Library Path, click "Add Project"
   flex_framework should be an option.
6. Check that you can build.
7. Check that you can open a framework class and set a breakpoint. (ie, hit cmd-shift-r, type Container...put a breakpoint in the constructor)

For the real good stuff, you can start adding all the other projects in http://opensource.adobe.com/svn/opensource/flex/sdk/tags/3.0.0.477/frameworks/projects . Just follow the above instructions, but replace "framework" with any of the projects. If you are using remoting, rpc is a must. I haven't played with any of the others yet.