CourseSmart is a provider of e-textbooks, or textbooks converted to a format that can be viewed on a computer. Now, it has brought students everywhere something even more useful: an iPhone application.
CourseSmart is free, but requires an account with the company. If you already use the service you just sign in and have immediate access to all the books you have bought. Browsing the reviews in the App Store, it looks to be a rather well focused first effort — there are some navigation issues, notably no double-tap to zoom, but apparently the texts are clear, and the search works very well.