Page curl & turn effects for iPhone Development
I put an answer to this question about the status of Page Curl effect.
We worked on a filter based on OpenGL ES and CoreGraphics that looks really close to the iBooks one and it's App Store safe. The filter is finished, we're working on a simple and easy-to-use API to integrate the effects.
Take a look here http://api.mutado.com/mobile/paperstack/
you can try XBPageCurl project , its more mature than using paperstack and freehttps://github.com/xissburg/XBPageCurl