Catabarex is right. Check BB. They're more than likely sold out of the regular english 2 mic version, so be looking out for the Spanish (2 mic) bundle. They're the same mics. Good Luck (these things went on clearance at BB months ago and people snagged them up).
Also check Sears which has marked them down.
No matter what, definitely go with the 2 mic bundle (especially if you end up paying MRSP). At least you get 2 mics and a game with it. You can always sell the other one and get some money back. The new version LIPS only has 1 mic, but MS wants to charge you the full price.