The Collaborative International Dictionary of English v.0.48:

Cicerone \Ci`ce*ro"ne\, n.; pl. It. Ciceroni, E. Cicerones.
   [It., fr. L. Cicero, the Roman orator. So called from the
   ordinary talkativeness of such a guide.]
   One who shows strangers the curiosities of a place; a guide.
   [1913 Webster]

         Every glib and loquacious hireling who shows strangers
         about their picture galleries, palaces, and ruins, is
         termed by them [the Italians] a cicerone, or a Cicero.
                                                  --Trench.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cicerone
    n 1: a guide who conducts and informs sightseers