In both of iPhoto’s book views, you’ll notice a Slideshow button near the lower-left corner. It lets you display the pages of your book as a slide show. This opens up some interesting creative possibilities: you can take advantage of iPhoto’s book themes and page designs to create “slides” containing multiple images and text. (In the interest of readability, think twice about using a lot of small text.)
You can also send a “book slide show” to iDVD: while in book-edit view, choose Share > iDVD.