In this paper we review the use of techniques of positive currents for the
study of parameter spaces of one-dimensional holomorphic dynamical systems
(rational mappings on P^1 or subgroups of the Moebius group PSL(2,C)). The
topics covered include: the construction of bifurcation currents and the
characterization of their supports, the equidistribution properties of
dynamically defined subvarieties on parameter space.Comment: Revised version, 46 pages, to appear in the proceedings of the
conference "Frontiers in complex dynamics (Celebrating John Milnor's 80th
birthday)
