Stanza seems to be running again since its “demise” about a year ago. Good thing, too, as it gives you more choices in reading books on iOS, though development on the app seems to be frozen up to now.
There are, of course, many ebook readers on the iOS app store for the iPhone, the iPod Touch, and the iPad, including Apple’s very own iBooks app.
The following are some of the best, free ebook readers for iOS. Note that while the apps are free, many books need to be purchased from an ebook seller. Free books are available online on Project Gutenberg and other websites.