itachi was also at least a genin/chuunin around the time it happened.. there is what, a 6-7 year difference in age between itachi and sasuke.. and if that's right, he had already graduated from the academy by the time naruto and sasuke were born. so its at least possible itachi knows.

madara I would have to think might know as well (especially if he did summon the kyuubi to attack the village). but based on what we've seen of diuscussions between all the other atakuski members, they just refer to him (naruto) as the pain in the ass nine-tails host. which in the long run may be a BIG mistake