If you have books where you have publishing rights, you would be able to publish it on the ipad without any trouble. There are many online options that would help you to publish it online. One of the sites that can be counted as one of the top distributors is lulu.com. There is another online site known as dtp.amazon.com.
If you happen to visit this website, you would find that there are many documents that would help you to get some related information. You can also visit smash words that deal with Amazon, Sony as well as Apple. So you would be able to get many developer kits in the market. So you do not have to worry when you wish to publish your book on the iPad. You should always try to check and modify the articles before you wish to publish it so that you can get rid of any errors.