IBooks is an application that allows you to read digital books on your iPod Touch, iPad or iPhone. The application is free to use but the actual eBooks themselves cost money to purchase. If you want to put an eBook into your copy of the iBooks application you will have to do so by downloading it from within the built-in electronic book store contained within the app.
Tap the "iBooks" icon on your device to open the iBooks application. If you have yet to download the application, tap "App Store" and "Search." Search for "iBooks" by name and tap "Download" to download and install the application.
Tap the "Store" icon in iBooks. Browse through the iBooks Store and select the eBook you would like to download. The iBooks Store operates identically to Apple's App Store, with the exception being that it sells electronic books instead of applications. Tap the "Purchase Now" icon when you find the eBook you want to add to your iBooks collection. Your iTunes account will be charged for the price of the book and it will be downloaded to your device.
Exit the iBooks Store and return to the main iBooks program window. Tap the icon of the book you downloaded to view its entire contents on screen.