I would recommend How To Cheat Flash CS4:
It's up to date, covers all the new things in CS4 and has tons of handy tips and tricks
gained from professional experience that will save you a lot of time.
From Adobe Devnet:
About the author
Chris Georgenes is Art and Animation
Director for Acclaim Games. Prior to
Acclaim, Chris spent eight years as a
freelance Flash designer and animator
for clients such as Adobe, Microsoft,
Ogilvy, Digitas, Yahoo!, and AOL, to
name a few. His work has also appeared
on broadcast networks such as ABC,
HBO, and the Cartoon Network. He
maintains mudbubble.com as his online
portfolio and keyframer.com as his
blog, animation resource, and
discussion forum. Chris is the author
of How to Cheat in Adobe Flash CS4
(Focal Press) and is currently writing
Flash Studio Techniques (Adobe
Press/Peachpit Press). When Chris
isn't designing, animating, or
writing, he teaches the Flash
animation course for Sessions.edu, is
an active Adobe Certified Expert
member, continues a 32-year career
playing drums in a professional Motown
dance band, and somehow balances the
rest of his time with his wonderfully
supportive family.