Walker Books have just launched enhanced e book apps for the iphone, news here in The Bookseller. Walker Books have teamed up with Scrollmotion to develop them and one of my Books The Ravenous Beast is one of the first ones available!
I mentioned this back last year when I got an iphone myself and my three year old at the time loved drawing and looking at photos on it. I am just downloading it now from itunes. I'll show it to Aoibhe later and report back to let you know what I think!