Hey, check this out.
<a href="http://chaos1.hypermart.net/wrw/">
http://chaos1.hypermart.net/wrw/</a>
It doesn't explain many of the features of each religion but it gives you a good idea of how the different denominations emerged and how they're related to each other. Looks like a bunch of the protestant denominations just kind of "sprang up" during the late 1700s - early 1800s in the US, the first and second "great awakenings" of spirituality in the U.S.