Apple just announced a new version of iBooks. It's got a continuous scrolling reading option, which is pretty great. It's also got its own iCloud-enabled version of Whispersync, that will sync your current page across any device you're reading on—iPhone, iPad, etc. You've also got more sharing options, like copying and sharing quotes.
It's got support for 40 languages (all available in iOS 6), and is available to download today.