You mean no one has mentioned Brian Keene, author of The Rising, City of Dead, etc.? Thanks to his web page, I learned that he has affordable MP3 copies of several of his books. There are some Kindle and Sony editions available, too.
Here is his web page:
Even cooler, a couple of his stories take place in Spring Grove, PA, which I'm sort of familiar with. It was really neat reading about ghouls attacking people in a place I'd driven through and shopped in.