In short, CS5 will have some support for AS3 conversion to ObjC.

http://labs.adobe.com/technologies/flashcs5/appsfor_iphone/

Some opinions:

http://eon.businesswire.com/portal/site/eon/permalink/?ndmViewId=news_view&newsId=20091005006358&newsLang=en

http://jeffrock.com/post/205303852/on-authoring-iphone-apps-via-flash-cs5

http://nikf.org/post/205314635/my-favourite-line-in-the-flash-to-iphone-guidelines