I believe I have iBooks working. I redownloaded a book I previously purchased from the iBook store and everything seemed normal.
Restored to iOS 5.01 via iTunes.
JB with Redsnow 9.10b3
Installed iBooks via App store
Installed iBook Fix2 from Cydia (you need to add a repository - Google it)
All is good. I tried many different versions of the above instructions but this exact procedure did the trick.