Yeah, without a doubt. But just for those who actually do doubt: http://img.photobucket.com/albums/v3...HakuZabuza.jpgi think the other guy is haku
Anyway, I would assume that Zabuza had done something bad to Kimimaro, seeing how he's in a combat pose with his cute little bone dagger and all. Perhaps massacred his village, perhaps touched him in "bad spots." Who knows.