Any books you’ve downloaded from the iBookstore will be automatically added to your iTunes library the next time you sync your device with your computer. To do this, your computer must be authorized with the same account that was used to download the books from the iBookstore.
iBookstore
The iBookstore is an ePub content sales and delivery system that delivers iBooks to the iPad and to other devices running iOS 4.0 (namely the iPhone and the iPod touch). The iBooks shelf turns around, revealing the iBookstore. From here users can purchase various books from Apple. iBooks can sync between devices, so one could start reading a book on one device and continue from where one left off on another.
Prior to the unveiling of the iPad, publishers Penguin Books, HarperCollins, Simon & Schuster, Macmillan Publishers, and Hachette Book Group USA committed to producing content for the iBookstore. Additional publishers were invited to participate on the day of the product announcement, January 27, 2010.The iBookstore also provides access to the 30,000+ free books available from Project Gutenberg, and it provides content channeled through Smashwords, allowing independent authors and publishers to self-publish.