Is it just for American people?, eg if a person were on holiday could he or she enter the contest?

Its just for Americans :P

Are you sure about it?

There was a British guy in it last year. Think he had lived there for a couple of years though.

If you live in America you can apply, thats why the British guy from last year was allowed to audition

You need to have your work visa, but then you can apply no matter where you're originally from.