I don't think there is... All iTunes (and generally all specific-store-bought) material is subject to DRM protection, which only lets you play or use the content in their own environment with the right credentials. The only format I know of that is a bit more widely available is DivX but you need a DivX certified device and a valid account to prove ownership.
Welcome to the forums. I'm going to go with Spookdroid. You bought an Apple-specific format, so you won't be able to (legally) convert it to play it on a non-apple device.
And this is why I never buy anything that's not platform-independent (music, movies, books, etc). Not when there's so many options out there to spend your money on that will work on all devices, regardless of manufacturer/OS.
Sorry, as I know that's not the answer you were wanting to hear, but it is what it is.