There are many Christian sites that criticize Mormonism. so that you can easily find what you need in order to understand what Mormonism is. But I found a site that easily explain what Mormonism is from Mormon perspective, not Christian. it is interesting, but listen with caution. I check this site as my research effort and to learn more before I apply any criticism.
http://mormonsmadesimple.com/
another source http://mormon.org/