Got permission from Doug to announce that my new version of The Adobe Photoshop Layers Book for CS4 has been released. The new version has an additional section on working with HDR and creating images that manually composite bracketed images using Blend If, Masking and layers. 60 all-new pages, a complete re-working of the rest of the materials, and enhanced support (there is a new Photoshop Layers discussion forum dedicated to the book).
Check out the book on Amazon: http://aps8.com/taplbcs4.html
If I can answer any questions, please ask!