If you haven’t already started playing with the Flex 2 public beta, make sure that you first check out the beta 1 to beta 2 changes / migration document.
We did an API scrub between beta 1 and beta 2 so the names of a lot of the APIs changed.
Also, make sure that you type all method returns, or else you will end up with a ton of warnings. If your method does not return any values, then type the return as void, like so:
public function foo():void
//dont return anything
You can view the document here.
You can download the Flex 2 beta bits (Flex Builder 2, Flex Framework 2, ActionScript 3, FlashPlayer 8.5) from here.