A rumor from AllThingsD indicates that Apple may be giving podcasts their own app in iOS 6. Developers testing the software have been reporting that podcasts are missing from the iTunes app: though it's possible to find purchased ones through Music, users say they can't search for or download new podcasts. According to anonymous sources, however, that doesn't just mean the build is unfinished. Instead, Apple is reportedly planning a dedicated podcast app. That would put podcasts on the same footing as books, which have their own app in iOS 5. The desktop version of iTunes would continue to sell all kinds of media content.
Audiobooks and iTunes U content are apparently also missing in iOS 6, leading to speculation that they're being moved out of the main app as well. If this happened, it could both slim down the store and provide more exposure to different types of media. However, since this is a beta, we'd be hesitant to pin too many theories on these changes yet.