Flash is an excellent platform for game developers. It is perfect for online games, small games and promotional motion picture games. Flash games are easy to create and are very rich with graphics and networking capbilities.
Pushbutton engine is framework based on flash platform. Pushbutton engine is can help you get most out of other flash game frameworks.
Official quote:
“Build your game with reusable gameplay, physics, rendering, and networking components – some written by others, and some written by you. There are lots of great libraries for game development on Flash, and PBEngine helps you use them more effectively.”
How to obtain pushbutton engine?

You can check the official website for more information. Forum is perfect place to ask your questions related to PBE. http://www.pushbuttonengine.com/forum/
You can download SDK from here: http://pushbuttonengine.googlecode.com/
PBE is licensed under MIT license. So you can do preety much out of this engine. For more information on Pushbutton engine, check the official site.
http://www.pushbuttonengine.com