Grant skinner has released a new version of his html 5 canvas JS library.
Using The library is much like programming AS3, using the same name convention as the “drawing api” so there are DisplayObject, Graphics, Shape. U put stuff on “stage” by using addChild and removing with removeChild. Very similar to as3, making js programming to html5 canvas very easy for a as3 developer.

Very promising project.

Blogpost here.
See more here. http://easeljs.com/