Sort of.

Selling 1,000,000 coins on MtGox right now would take the price down to $0.10, with an average price of $19.64, so you'd net $19 million.

Of course, what would really happen is that everyone would see it happening and cancel their bids before the wave reached them, so you'd likely not be able to actually sell them all at once.

Leaking them out a few thousand a day, though, would be completely possible. And if done correctly need not move the market at all.