Inside of Apple's recently released Podcasts app for iOS is a redeem button, which suggests that a Apple built fee-based subscription service could be coming to the iTunes Podcast listing that Apple maintains.
This might also explain why there isn't the ability to manually add a RSS subscription to the app - it only allows you to subscribe to podcasts that are within the iTunes Podcast listing service.
A 70%/30% revenue share with Apple could be great shot in the arm to the podcasting industry that has to deal with finding sponsors, advertisers and other means of making money while trying to produce great content.
I for one wouldn't have any problem putting SSKTN and related podcasts behind a subscription service if Apple does a good job of making it easy to sign up, listen and subscribe to it.
Update: Looks like you can subscribe to non-iTunes Store podcasts after all thanks to Don McAllister's searching: