Media Arts Lab does all of Apple’s advertising. They even have a hand in picking which apps get to be showcased on those ads.
How do they decide which apps to put on the front page? They have the Media Arts Lab Apps Machine (blog). Some recent apps that have been showcased on Apple commercials were showcased here beforehand.
So, if your app makes it here, it might make it to a commercial – which leads to a few bucks in sales (so we’ve heard).
You can even subscribe to the feed – here. But probably not for long.