Going Beyond Flash MX
For the first time, Flash MX 2004 can now be extended beyond custom components and complex importer tools. Macromedia has extended the entire back end of Flash MX 2004. Now you can create your own behaviors, Timeline Effects, Drawing tools, and beyond.
There are a number of companies that have already come out with killer extensions for Flash. They include eRain with a lite version of Swift 3D called Xpress. You can also get extensions developed by Swish and Red Planet. There are certainly more to come.