As previously mentioned, Flash CS5 will give Flash developers the ability to build and deploy native iPhone and iPod touch applications. With yesterday’s iPad announcement, the importance of designing for different screen sizes has become even more apparent. Android phones also have different screen sizes.
Adobe has just posted a tutorial regarding authoring mobile Flash content for multiple screen sizes:
http://www.adobe.com/devnet/flash/articles/authoring_for_multiple_screen_sizes.html