Exciting news this morning! I awoke to see that Adobe has released a beta version of EDGE, the HTML5 motion and interaction Design tool on Adobe Labs, as well as theexpressiveweb.com/, an HTML5 showcase site.
EDGE will allow you to create Flash-like timeline animations purely using standards-compliant HTML. You can see a preview form the examples site below:
You can read a bit more about theexpressiveweb.com and the thoughts behind it on Adobe devnet at: http://www.adobe.com/devnet/html5/articles/introducing-expressive-web.html