Your Kindle textbooks will sync between all your devices…if you can find your books in the Kindle store.Amazon has made a semi-surprising jump into the textbook rental market, offering some of their textbooks as rentable downloads for the Kindle and Kindle apps. The announcement would have been more exciting had it been in conjunction with the release of the rumored Kindle tablet, but it could still come in handy when buying books for the upcoming school year.

Amazon’s big advantage in the race is their wide assortment of Kindle access points, with apps available for Windows, OS X, iOS, Android, Blackberry, and Windows Phone 7 (not to mention, you know, the Kindle itself). Since the service syncs your notes and highlights between devices seamlessly, you could cram for a test on your PC in the dorm, and double check vocab on the way to class on your iPhone. No competing service can offer this level of ubiquitous access.

Another great feature is the ability to set your own rental period, paying for anything from 30 days to an entire year. Most e-textbook services offer rentals for an entire semester, but there are plenty of times where you may only need the book for a month or so. Amazon claims up to 80% savings on the list price of the print edition if you only rent for a month, but obviously your mileage will vary.

Of course, the Achilles Heel of e-textbooks to this point has been availability, and so far the selection looks pretty grim. An Amazon search for the word “textbook” returns almost a half million print titles, and only 1,876 Kindle titles, and not all of those offer rentals yet. In my experience, it’s been the same story for everything from CourseSmart to NookStudy, but if anyone can twist the publishers’ arms it’s Amazon, so hopefully this will prove to be the breakthrough moment we’ve been waiting for.

[Via Techcrunch]