Here's a long article from Peter Berkowitz, of the Hoover Institute at Stanford, designed to address the current ills of conservatism. Along the way, he does as good a job as you'll find in describing exactly just what conservatism is and is not. Oh, he manages to through in a brief history of the excesses of the French Revolution, the debates at the Constitutional Convention, and the necessity of religion and virtue along the way as well. It's well worth the read for those interested in the theories that animate the political stage. It even presents a decent explanation of why liberalism isn't liberalism any more.
Take your time reading as there is a lot there and you might enjoy it more if you printed it out and read it at a more leisurely pace. That's what I did. It'll take twelve pages by way of warning. It's worth the reading though because very few great ideas, let alone philosophies, can be summed up on a napkin. Enjoy!
RealClearPolitics - Articles - Constitutional Conservatism