Actually, the bible does say it's flat. It's it's round, but uses the hebrew word for round (Chug (חוג)) like a flat coin is round, basically a circle, not the hebrew word which means spherical, like a ball (Dur (דור)). The view of the world at the time of the bible was that it was a round, circular, flat disk with a roof-like canopy that masked the heavens.
@Dust: There is literally nothing that shows that the Scriptures are the Word of God. If you cannot logically prove the existence of God, how can you prove that something is said god's word? That's why there are hundreds of religions, and even among Christians there's no consensus on which Christian Scriptures are the correct ones. The only thing that says the Scriptures are the Word of God are the Scriptures themselves, and tautologies aren't acceptable in science.