There are a couple of current threads that have a lot of information about the Amish, Popcornbird. See http://petoftheday.com/talk/showthread.php?t=114015 and http://petoftheday.com/talk/showthread.php?t=113932

They are a Christian sect, to answer your basic questions, and of German descent originally. The term they are sometimes called "Pennsylvania Dutch" misleads people, they are not Dutch. They are more prevalent in the East and Midwest.