I don't know if this is new with iBook in iOS 5, or I just never noticed in in iOS 4, but when you are in Bookshelf view (as opposed to the scrollable list) you can now swipe left or right to move through your collections. It seems to wrap around, so you can just start swiping either way and eventually get where you want.

I have a fair number of collections, so this is kind of cumbersome for me, but if you only had two or three, it would be a fairly fast way to navigate between them.

I had not seen that iBook library swipe either, but it works on my 4.3.5 iPad 2. Thanks for the tip!

Sent from my iPad 2 using iPF

Ahhh, not new then, but still handy. Thanks for letting me know.

Neat! Thanks for the tip!

Never, never, never give up -- Winston Churchill