One of the great new features you’ll see in Flash CS5 is XFL, the new file format that is XML-based. This gives you so much more control over your documents, and saves you from encountering nastiness like corrupt files. And Live Editing lets you edit your images easily from Flash. Just go to Photoshop, edit your work, and you’ll see it updated when you return to Flash.
For the details and a great video on this new Flash CS5 feature, see Valerio Virgillito’s blog post here: http://blog.mencio.com/?p=28