Of that, even I am not sure. But it seems to imply a culturally & economically Right libertarian, one whose emphasis is on such things as Constitutional history and the gold standard. As opposed to a culturally Left libertarian who may be more concerned with drug legalization and sex policy (gay rights, porn, abortion).
I think paleo-libertarians are also more likely to see statist restirctions of abortion rights a valid.
And the LewRockwell.com site sees Murray Rothbard as their guide (although they claim to be more influenced by Ludwig von Mises). The March 2003 issue of Liberty accuses Lew Rockwell of downplaying Mises's critiques of Rothbardian views.
However, Rothbard himself did not refer to himself as a paleo-libertarian, but rather, as an anarcho-capitalist.