The difference between Republicans and Libertarians

I'm not a fan of conservative ideologies. I see them as regressive and stifling. Too often there is a quasi-religious adherence to "free market" as the solution to all life's problems, usually accompanied by the corollary "lower taxes". Whether or not one agrees that these principles are bad policy, we can look at the current conservative-minded political parties and see how they employ various tactics.

On one hand we have the modern Republican party, which is supposedly conservative. On the other, the Libertarians, who are also conservative. (A smattering of other conservative parties exist but do not have serious political presence.) What separates them?

http://www.mydd.com/story/2006/7/24/6952/27282
http://news.yahoo.com/s/ap/20060721/ap_on_go_ca_st_pe/nuclear_safety
http://www.dailykos.com/storyonly/2006/7/20/21456/0875