Q: Can I download podcasts to my iPhone using WiFi without connecting to my computer and the iTunes Store?
A: Unfortunately, no. At this point, the “iTunes WiFi Store” application only supports purchasing of music content.
Audiobooks, podcasts and video content must still be purchased and/or downloaded via iTunes and synced to the iPhone from your computer.
For users who have jailbroken their iPhones, there are some third-party applications that provide this capability, however these are of course not supported by Apple, and hacking or jailbreaking your iPhone may in fact void your warranty, so it’s not a recommended solution.
Alternatively, there is the possibility that the coming iPhone Software Development Kit (SDK) may allow a third-party developer to write an application that provides this sort of a feature.