According to a post at TUAW early developer builds of iPhone firmware v.2.2 include the ability to download podcasts directly to the iPhone.
This would explain why Apple rejected Alex Sokirynsky’s Podcaster last month for duplicate functionality. TUAW notes that the blue link at the bottom to "get more episodes" doesn't work in this build, though.
MacRumors notes that firmware 2.2 also gives you the option to rate an application before deleting it and that leaked screenshots of iPhone 2.2 Beta 2 reveal other new features:
- Google Street View - Public Transit Times and Walking Directions - Location Sharing