You can download the update directly on your device through the Apple App Store or by using the link which follows:
This is the first major update to the iBooks application since earlier this year when Apple introduced iBooks version 2.0 with education-centric features.
Apple iBooks 3.0 for iOS has the following new features and improvements:
- See all your iBookstore purchases in iCloud—right on your bookshelf with iOS 6
- Scroll vertically through your books with the flick of a finger using the new Scroll theme
- Receive free updates to purchased books—including new chapters, corrections, and other improvements
- Look up definitions for words in German, Spanish, French, Japanese and Simplified Chinese with iOS 6
- Share quotes or thoughts about your favorite book with friends on Facebook, Twitter, Messages, or Mail