Currently Being ModeratedJan 11, 2013 6:08 AM (in response to fred7518)
iBooks are for reading on your iPhone and iPad (iOS devices). They can't be read on a PC or Mac.
which says in part,
"Books you purchase on a computer must be read with the iBooks app on an iOS device."
"Note: Books are only readable on iOS devices that have a compatible version of the iBooks app installed."