I’m sure based on the activity you’ve seen in the Flex 3 branch you’d think not much is going on, however you’d actually be wrong. Alex has been leading an effort on a feature we call the Marshall Plan. This is a play on words but is meant to solve a problem that we think folks building big pieces of software may face: the fact that sometimes you can’t recompile everything to be on the most recent version of Flex. Additionally it is meant to solve a common use-case we hear about with AIR apps especially, the desire to act as a portal where SWF content can be loaded from multiple domains.
ETA: I forgot, I’ve done some small updates on the Flex 3 page to reflect upcoming dates.