The only way I've seen that its possible is via iTunes. iBooks doesn't have anyway that I can find that allows you to change any of the data even in books I've created with Pages. But in iTunes even though the Book option is not here anymore to browse the library when I connect my iOS device the Book section is still there. You have to use the Books Sync option on your iOS device to get a book on your iOS device and then once its on the iOS device you can change the meta data etc like before. Doesn't seem like this was thought out to well, I had expected iBooks to operate like iTunes but it doesn't even show devices to drag your books too. I would have preferred them keep Books in iTunes and just allow me to open the books from there, like the digital booklets for music.