In several posts here, I've stated that majority of Christians (by denomination, at least) are not Young-Earth Creationists. While looking around to see if there was any formal data confirming my own observations, I discovered that there's even a name for religous acceptance of the theory of evolution: "Theistic Evolution."
And this section breaks down the various beliefs by denomination:
I'd say that page, and its references, effectively confirms that the majority of Christians are not Young-Earth Creationists. It also pokes some rather large holes in two common creationist tactics: their tendency to rely on "appeals to the majority," and the claim that people only accept evolution because it "allows" them to not believe in God.
Beyond that, it appears that Islam is the only major religion where the majority of followers believe in anything even remotely similar to Young-Earth Creationism. Quite amusing, considering that many in the anti-evolution crowd are also anti-Islam - strange bedfellows indeed.