"at the expense of the schools - who must now prepare a course, offer a course and find someone to teach it, even if not enough sign up for it."
Okay, I think the law is silly. Even if, as I understand it, the course merely needs to be offered. Christianity is not the only religion, nor the Bible the only scripture, that has had a huge impact on history, western and otherwise. (And Nanc, if you're doing it for moral reasons, that's even more wrong. Don't the righties want us not to teach tolerance or other "leftwing" values?) But this comment displays a lack of knowledge about how schools work. (I'm not saying the poster is dumb, mind you. You mightn't know this if you don't have knowledge of how schools work.)
If the course is meant as a social studies course, history of the Bible and its impact on world religions, then any certified/licensed HS social studies should be able to teach it. (Just as any HS SS teacher can teach Civics or western history or world history.) If it's intended as a literature course, any certified/licensed English teacher should be able to teach it. (The part about what values they inflict upon it is different--it's not about ability, but about approach. If it's a public school, there should be no belief or disbelief averred by the teacher, at least not without being open to argument.)
As for preparing the course, it might mean they have to prepare it (design it); it might not. It depends on how scheduling works in a school and how the assigned (or volunteered) teacher works. If, for instance, the scheduling takes place early in the spring before the course is to be held, and not enough sign up for it, then the course is dropped and no one has to design/prepare it. And many teachers don't fully design a course before Day One. They don't necessarily have to, either. Depends on teacher, admin, and school culture. I have a course in the fall that I haven't designed fully. I know the texts; I know the skills and dispositions I want the students to have at the end; I know some of the final projects and some assignments along the way. But most of that is in my head. I haven't really begun design in earnest, and the class begins next week. (Of course, now we're approaching educational philosophy and teaching styles, and learning styles, so we'd have to start a new thread. Or talk offlist.)
Thus endeth your lesson (and quite a tangent it was).