Two updates last night successive versions of the Corona jailbreak solution were launched in Cydia, the first solves the problems with displaying DRM content in iBooks and the second solves the functionality problems of the first one. Unfortunately the two versions did not work properly on iPhone 4S with iOS 5 installed and many users had quite big problems after installing them but the good part is that version 1.0-8 is now available and it should work without problems even on iPhone 4S with iOS 5 and jailbreak with Absinthe.
If you have an iPhone 3GS with an old bootrom, you don't need to install Corona, according to saurik's advice, so use latest version of redsn0w to solve iBooks application problems.
