That's a Specialized crank, isn't it? It really shouldn't break unless it is crashed, IMHO. Even if you rode it aggressively, skidding and all that, and you weigh 200 pounds, a crank mustn't crack like that.
Whatever... Maybe drop a line to Specialized... Not really a warranty issue as it's 2 years old, but at least they'll know they're makin crap.