That's what I thought.
This isn't the only track, but it is obviously the best out of next week's DLC for Rock Band. Next week on all three major consoles will be the Lady Gaga Pack 01. A pack consisting of "Poker Face," "Just Dance," "Monster," and "Bad Romance" of Lady Gaga fame. So if you are a fan of her "music" for some reason, you can give her tracks a whirl. But the Cartman Poker Face should totally be on the list of downloads once it becomes available.