iBooks

I am now considering the design for the iBooks as part of my range of deliverables. This is an area that I am not particularly familiar with in terms of using as I have only just got an iphone and have not really used an ipad. I am interested in how I can make the design of the ibooks stand out. I think that maybe promoting the ipod/ipad theme as 'free' when you purchase the iBook could add an extra incentive to buy the product.