"To cross out with lines or other markings; to annul or invalidate."

That would be the definition of cancelled. Or is it canceled? To my surprise and amazement, both are correct. Frankly, I don't understand the need for two correct spellings of "cancelled" (my choice of spelling). With the English language already in steady decline thanks to rappers and AOL IM, why increase the frustration of those of us who actually care if they're spelling something correctly? Argh.