The very first book on AutoCAD 2008 is now available from upFront.eZine Publishing. "What's Inside? AutoCAD 2008" details the new features and the changes -- all 152 of them.
The ebook has over 200 figures illustrating the changes, and includes commands not documented by Autodesk.
There's more details about the 110-page PDF ebook at eBooks.onLine, and you can purchase it for US$16.50 through Paypal. After AutoCAD 2008 ships, you get a free upgrade to the ebook with last-minute info.