An important note, though, is that while the CourseSmart etextbook version is typically cheaper than the hard copy textbook, the "e" version expires after 180 days.
On the plus side, there's something wonderful about the instant nature of acquiring the etextbook in this manner.
But on the flip side, there's something unsettling about the almost "instant" nature of losing the etextbook purchased in this manner.
To ensure students get the most residual value (ie, ability to hold onto for later use, or re-sell) for their textbooks, it would be wise to remind them of the existence of the expiration date so that they can make an informed decision when deciding which textbook version to buy.
More info listed here on ReadWriteWeb:
http://www.readwriteweb.com/archives/cousesmart_college_textbooks_on_your_iphone.php