Frances from Google Book Search writes in with news of their embedded book previewer:
It allows people to programatically search, access, and preview books digitized as part of Book Search. For an example of the viewport in the wild, here's the Book Search iGoogle gadget that incorporates the previewer. Just install it on your iGoogle page and then click on a book to see a preview.
I haven't seen a lot of cool uses of the previewer yet (which is why I'm pinging you), but I think there is potential for it. For example, I want to see someone annotate a bunch of books (maybe make an app engine app that lets people do this generically?) and then allow users to navigate around the book based on the comments – imagine the potential for collaborative reading or interpretation of a text.
Using the API you can move forward or back in a book, zoom in or out, show the current page number, jump to a page, or search within the book.
My Google Book Search Library,
(Thanks, Frances!)
