I created an open book (recto verso) but unfortunely I only have a Dutch
tutorial. To help you I made a webpage where you can download an example of
the open book for version 2003 and 2007. When you open the presentation in
your own English version of PowerPoint you will see how the book is composed
and which effects I have used to turn the pages.
Hope this is useful.
The link to the webpage: http://users.skynet.be/avdg