Corona 1.0-5 out now to fix iBooks issues
There have been many reported issues with iBooks throughout the entire jailbreaking history of 5.x firmware. Today Corona 1.0-5 was released to solve these issues on the untethered 5.0.1 jailbreak. 1.0-4 was released about a half hour ago but Saurik quickly released 1.0-5 to force Cydia to reboot your phone after installation since many users did not realize the device needed to be rebooted for the fix to take effect. Another method called iBooksFix2 was released a while back, but many people still reported problems with iBooks. If you are having issues, be sure to go into Cydia and download the newest Corona update to fix your iBooks problems.
If iBooks is still not working for you, let us know below and we will try and help you figure it out!