Sony Computer Entertainment has registered trademarks for "PSPComics," "PSPMagazine," and "PSPBooks." Hideo Kojima, of Metal Gear fame, alongside Frank Miller, of Sin City fame, revealed in a recent interview with Famitsu that he would be releasing a "digital comic" version of Metal Gear Solid for the PSP. It will be slideshow style, but not just a simple comic conversion -- the developer stated that there would be a few gimmicks added, such as the scene changing when you go back to previous panels, and how you'll have the ability to change angles.
Hideo Kojima more or less confirms this on his blog, where "Metal Gear Solid BD" is listed as a title he is developing for the PSP.