A recent Gallup Poll found that more than 38 percent of Americans believe in ghosts. This is up quite a bit from ten years ago, when only one in four people said they believed.

And this belief helps ghosts. Why?

It's pretty simple, according to people who call themselves ghost hunters: You have to believe in ghosts to see them.

The more familiar truism, of course, is "seeing is believing." But ghost hunters have turned it around on purpose. In their ongoing debate with skeptics, they've upended the cliché and used it as a weapon to bolster their case for the existence of spooks.

And what's wrong with that?

It depends on which side of the haunted fence you're on. If you believe in ghosts, there's nothing wrong with it. But if you're a skeptic, it's a huge problem.

"If you go in to a place that's supposed to be haunted, you're tuned up [to believe] already," explains world-famous skeptic James Randi, who has promised to pay $1 million to anyone who can show evidence of a paranormal, supernatural, or occult event under controlled circumstances.

So far, no one has won the money, although Sylvia Browne, who claims she is a psychic, agreed in September 2001 to put her powers to the test.

You could have a chance to win that money, too--if only you could find a ghost. So how do you go about doing that?