Apple TV is based on iOS but here's a quick heads up which confirms that Apple TV runs iOS. Apple has just posted iOS 4.1 for Apple TV on their servers, I know it's not useful for you because you don't need to restore to it as it comes with it! But this is just a proof.
It would be very interesting if the hackers could jailbreak it to add new features and install apps that would help you to make things you can't imagine. Download link posted below:
Download iOS 4.1 for Apple TV