I hope to god it isn't Help!, it's a great song.. I just want it as DLC. :s But if this is a clue and they aren't just saying "when you get the game, you'll be able to figure it out." Then it seems likely. But, they could be just giving a hint that they aren't revealing the last song till 9/09/09.
9/9/09: A dream come true.
Let's get some Coldplay!
So they've said from the beginning that you can play all songs immediately. Is that not going to be the case then? Because if you really can play all songs right off the bat, I'm not sure what the point is of holding one back.