Oh wow! I sure hope it is, but I don't recall reading anything about that. Make sure you dry it out fully before turning it on. Do you have insurance for it?
I don't think that its waterproof. Maybe it seems to be ok in the beginning, but after a while, you can see a watery surface beneath the screen. This is from my personal experience.
Definately not a waterproof product. Although maybe this is something they should do for the next round of iPhones! If they can make a portable camera that looks totally normal be waterproof up to 30m, they can make the iPhone waterproof!