Don't expect this to show up on your iPhones anytime soon. Real has submitted their Rhapsody subscription service app to the iPhone according to a report by GDGT. Apple has been pretty strict on its "duplicates features of existing applications" with respect to music applications being copies of iTunes mobile. However, with the ZuneHD coming along with a streaming subscription option, Apple *might* consider letting a subscription app hit the iPhone or even unleashing a service of their own..
Another all-you-can-eat subscription streaming service, Spotify, is also currently in App Store Purgatory after