Apparently in Isaiah chapter 40, Isaiah wrote that the earth was a "circle", and apparently there are some who argue that the translation should actually say sphere, and not circle.
(I also liked the verse in Job chapter 26, about how the earth hangs on nothing : p)
There seems to be good reason to believe the bible actually tells us that the earth is in fact round, and I havent actually heard any real bible verse that claims that the earth is flat? Seems to me that God told us that the earth is in fact round : p