There is nothing wrong with teaching creationism per se, people are free to believe what they want, not that I believe it in myself. That being said creationism, Intelligent Design etc.. only belong in religious classes. They should not be taught in science class along with evolution.
Children - especially young children - sometimes have trouble differentiating the difference.
The bible should not be taught IMO as a science book under any circumstances. As a Catholic for example I was taught as a child that virtually all of the old testament was apocryphal