Just how excited are you to play Final Fantasy XIII when it ships in North America next March? Enough to sign up for a Twitter account? And to tolerate some disc swapping?

Good, because Microsoft and Square Enix are giving away something Final Fantasy XIII related if you're willing to re-Tweet something on their behalf. What is it? Not a fifth DVD containing extra FF XIII content, unfortunately, but something mysterious, something that can only be obtained via Xbox Live.

Adding to this Final Fantasy XIII-Xbox 360-Twitter synergy is next week's dashboard update, which brings Facebook, Twitter and more to Microsoft's console. So you can join in on the co-marketing fun from the comfort of your couch.

Square Enix isn't saying what the secret prize is yet, but word on the street is that it's worth the nominal effort. I'm hoping for an Odin summon in horsey mode that my Xbox Live Avatar can ride upon. Please, Square Enix, don't let me down!

Final Fantasy XIII - Register. Tweet. Win. [Xbox.com]