Amazon just announced the availability of textbook rental through their Kindle service, which allows students to “rent” a textbook for any device that runs the Kindle software. The rental length can be between 30-360 days (you pay on a sliding scale depending on how long you need it) and can be extended after the original rental if needed.  In conjunction they now have a Textbook portal for searching out what you need, including the ability to search an entire list of ISBN numbers at once.  It will be interesting to see how popular this service becomes as we move into the start of school in a few weeks.