I've heard it most often pronounced 'boy', so that it rhymes with 'toy'.
Maybe that's the North American version? Second most common is 'boo-ee', rhyming with --- hmmmm --- 'chop suey'. And come to think of it I HAVE heard it pronounced 'boy-eee' - exactly as that's written! So that makes three alternatives. And yes, I've heard different pronunciations within the same small towns as well. Must depend on the ethnic background of the singer/speaker?

daylia