I love books.app. For me, reading e-books was really the one killer app that the iPhone was missing. Lots of the other programs are fun, but having the ability to carry books with me, read them one-handed on the subway or in the dark, or anywhere--that really makes the iPhone the absolutely perfect device (I like its core functions, too, of course). But books.app only takes .txt or .html ebooks. So I wonder if people have good recommendations for where to find those? Free is good, but I'm willing to pay, too, if the books are good. One good tip is that Karl Shroeder's first SF book, Ventus is available in many formats, including html. That's a good read, and free. Any other suggestions?