My BlackBook is like this also, the screen appears to be slightly rotated so when you close it the right side of the screen sticks over the rest of the machine by a fraction of an inch. I just put it down to the fact I've had the laptop over a year and every day it gets opened, closed, thrown in my rucksack, bumped across the country in the car, and the plastic has warped accordingly.
However mine does not seem to be as prominent as yours, and if it is so far off that the magnetic latches are having trouble matching up, then you should have a case to get it looked at, though no guarantees whether AppleCare will cover the costs.
Apple has historically not been as ready to replace warped plastic frames as they have cracked plastic frames, a move I feel may be because a crack can directly impact the cases integrity.
Good luck! Wolf ∑:p