Most of the comic books released on the iPad and iPhone have been inside of special apps (many of which are run by ComiXology, actually), but here's another option. Comic book publisher IDW is set to release some graphic novels and comic books through iBooks, meaning that you can buy them right inside Apple's official e-reader app. 20 different graphic novels are coming out in the first round, ranging from genre stuff like Star Trek and Doctor Who, to licensed titles like Dragon Age, and older stuff like Locke & Key and Bloom County. Each should cost around $6 to $10 (which is competitive, especially compared t