Hey guys,
Wasn't quite sure where to post this, so sorry if it's in the wrong place.
Just wanted to let you know that I've released my ActionScript 3.0 port of Erin Catto's Box2D.
It's open source, and under the zlib license, so it's free for use in commercial or non-commercial projects.

Check out the demos here (along with a link to the download, which includes the source for the engine and the demos), it showcases most of the features I think, easier than listing them.
http://box2dflash.sourceforge.net/

Anyway, let me know what you think, and if you use this in a game or any other application, I'd love to see it (contact info is on that page, and in the readme).

Cheers.
-Matt