I just happen to know the answer to this question
Prices tend to change on Oct. 1 around WDW (though of course, minor changes occur through the year at various places, usually at a low level).
That means October and November is a very busy time for me. I print new copies of the book right after that. Well, that's what happened last year. And then I learned that many of the non-Disney restaurants (especially Downtown Disney and Epcot lessees) updated on December 1. So it's possible I won't print until after those changes are made, meaning the 2008 version of the book won't be available until early January 2008.
That said, the book currently for sale is actually version 2007c (it was most recently updated and printed in mid July 2007). I only print small quantities so I can update it constantly.
The 2008 version may be worth waiting for. It will have complete menus and prices for Universal-Orlando and IOA, and it will list all the restaurants on International Drive too.
I'm toying with altering the format in WDW, too. For sit-down restaurants, I may discontinue listing the appetizers and desserts, and only focus on the main courses. With all that extra space, I am considering adding complete dish descriptions and details.