AS3

Definition

from Wikipedia

ActionScript is a scripting language based on ECMAScript. ActionScript is used primarily for the development of websites and software using the Adobe Flash Player platform (in the form of SWF files embedded into Web pages), but is also used in some database applications (such asAlpha Five), and in basic robotics, as with the Make Controller Kit. Originally developed by Macromedia, the language is now owned by Adobe(which acquired Macromedia in 2005). ActionScript was initially designed for controlling simple 2D vector animations made in Adobe Flash(formerly Macromedia Flash). Later versions added functionality allowing for the creation of Web-based games and rich Internet applicationswith streaming media (such as video and audio).

Tutorials

Some tutorials for beginners from http://www.flashandmath.com/ 

Simple 3D Drawing in Flash CS3  A step-by-step tutorial that walks you through the basic techniques of 3D rendering in ActionScript 3. We begin with a revolving cube and end with a parametric surface.

Loading External Clips and Videos in Flash CS3.   Learn how to load and control external swf files at runtime, including those contaning Flash Video (flv) files.

3D Particles Experiments in AS3 and Flash CS3  Four stunning 3D particle experiments by Dan Gries. A sphere separates into several spheres based on the particles color; particles revolve and tend to a gravity center; particles transition throughout a cube, and more. You can rotate and manipulate the particles in 3D.