The easiest way to do this would be through iMessage. Just foward the text to yourself, and in the iMessage settings on your iPad, make sure the settings are to recieve them from your email and your phone number.
Keep in mind, with doing this you will lose the info of who the original sender is.
@Stetrain, you still have to go to the App Store, download iBook then save it. Imagine if you couldn't save documents on your Mac without having to go and download an app first.
It's basic functionality that should be in the operating system.
Hear, hear! Not allowing basic file management on a supposedly high-end and expensive mobile phone is extremely limiting and frustrating. As is the use of the marketing term "the world's most advanced mobile operating system" (not quite, Apple).