A couple weeks ago I heard an excellent program on NPR about the separation of church and state. On Sundays at 4PM local, Krista Tippett hosts the show Speaking of Faith.
On the October 30th show, Krista Tippett interviewed Steven Waldman (here) who runs the BeliefNet.com website. Steven Waldman speaks ostensibly about his book Founding Faith however he delves quite a bit into the early role of Evangelical Christians in establishing the separation of church and state.
I would highly recommend his book as well as listening to this podcast.

I liked this interview a lot. The most interesting thing is this author really does a 180 from his original intent in writing the book. For him, it all goes back to faith. Religion is best when it’s left alone and out of government.
I might just have to pick up this book.