Don't forget your local library as your life becomes more dependent on electron based entrainment & information. Although most libraries (not all) are keeping those things called books, your local library is probably ahead of the curve in providing digital content for your i-devices. Waco-McLennan County has numerous online databases including NetLibrary. Why is this so cool? NetLibrary lets you check out e-books and digital audiobooks wherever you have an internet connection. Recently, the Waco Library has joined many other libraries across the nation in using Overdrive, a digital media delivery service that integrates with your iPhone, making access to the digital content even easier.
Here is the link to the Overdrive site where you can get the software you need.