Lots of new books are coming that dig into Creative Suite 4. But if you’re looking for something fast and free to whet your appetite, download a copy of the 70-page CS4 Superguide at PhotoshopCafe.com:
Link: CS4 Superguide
Note: You’ll need to subscribe to their mailing list for a download link.
And, for an updated collection of new and upcoming books about CS4, check out Amazon’s new CS4 Books page:
Link: Amazon CS4 Books