iBooks 1.2.1 Detects Some Jailbreaks, Disables iBookstore Purchases in Response
Social Apples details a change employed in an update to Apple's iBooks application released last week that detects whether a device has been jailbroken using one of several tools, and if the device has been found to be jailbroken, refuses to ...
http://www.macrumors.com/2011/02/15/ibooks-1-2-1-detects-some-jailbreaks-disables-ibookstore-purchases-in-response/