There are many resources to get you started with game programming in ActionScript. Many articles and tutorials will discuss the basics, but if you really want a quick start, a game engine is a great help. This post lists a number of interesting options.
Game engines come in many flavors, some offer you just a framework for showing 3D images, others almost don’t require any programming at all. Here are some of my favorite ones.
If you want to create a 3D Flash game, you could start with one of the 3 major 3D engines (Sandy, Papervision, Away) But if you want even more help, there’s Yogurt3D. While the others are more general 3D engines, Yogurt3D is directly aimed at 3D game development. It has higher level constructs, like animation, to support game development. My main gripe is the lack of documentation. There is a pretty extensive tutorial, but that’s about it. There’s no forum, so you’re going to have to Google a bit (but there seems to be quite a few articles around).
An isometric engine. If you like the style, you’re going to love this engine. Again, the documentation is lacking, but there’s a great demo that might convince you to give this engine a try.
This is the way to go if you want to create a 2D game. There are detailled tutorials to get you started with almost any ActionScript editor immaginable (including FlashDevelop). The engine is still under very active development and there’s a lively community that will surely help you out if the wiki is insufficient.
Probably the most known, best documented and most active game engine for ActionScript. The PushButton Engine is build around the concept of “components”, which, to me, feels very natural, especially for a game. Watch this short introduction to get the gist of it (via BIT-101)