I built an RSS app in Flash CS3 using ActionScript 3. The bulk of the supporting classes came from Mike Chambers' AS3 XML Syndication library, which was written a while ago. The parsing and date utilities needed to be modified so it would work with Flash 9 and AS3, but the essentials were there to work with.
I tested a number of RSS 2.0 feeds, such as FlashGuru's feed and a few from Feedburner. Now it's a matter of improving my display layout in a Flash object that will be embedded in a Web page. Fabuloso!
Aloha, Joe