I'm interested to know, are the things described in your book programming projects? If so, what prior knowledge is required, e.g. Objective C, XCode? If not, what is the nature of the "hacks", as presumably this isn't aimed at jail-broken iPhones!
iPhone Geekery covers getting the most out of your iPhone without actually having to write code. The book contains 50 projects covering everything from using your iPhone as your recording studio or backing track to unlocking, jailbreaking, and recovering extra space from the OS partition.