Google announced updates to some features of Google Books today.
The most interesting thing I see is the contextual "search within this book" results page, showing clips of pages where search terms appear. This should make evaluating search result relevancy a HECK of a lot easier than it was prior to this update.
Also interesting is the enhanced ability to embed books within a website or blog such as:
One simple copy and paste line allows you to embed a book! I think I see a major update coming to the Google Books Index to follow suit!