Buying textbooks is annoying! They're expensive, heavy and instantly useless after finals. Amazon is trying to change the game with Kindle Textbook Rentals, it's a service that lets students rent Kindle textbooks to save tons of money.
Students can customise their textbook rental period (anywhere from 30 to 360 days) and from the looks of it, a semester-long rental is significantly cheaper than buying the book (I got a ~$US50 rental on a $US110 book). Amazon says it'll have "tens of thousands of textbooks" available for renting, all of which will use Kindle features like Whispersync, highlights, notes and the ability to use it on any Kindle app (iPhone, Android, etc.).
As much as this seems like the future of textbooks, I'm not sure the regular Kindle is exactly the best tool for studying (can you imagine thumbing back and forth on that thing?). Good thing it works with the Kindle DX too. [Kindle Textbook Rental via TechCrunch]