Essential ActionScript 3.0
The book focuses on the core language and object-oriented programming, but also adds a deep look at the centerpiece of Flash Player's new API: display programming. Enjoy hundreds of brand new pages covering exciting new language features, such as the DOM-based event architecture, E4X, and namespaces--all brimming with real-world sample code.
I use these main import statements for the begaining of all my Actionscript 3 projects. The last two are custom classes that I use for tweening. One class is called Tweener and the other is called TweenLite.