  We develop a semiclassical theory of nonlinear transport and the
photogalvanic effect in non-centrosymmetric media. We show that terms in
semiclassical kinetic equations for electron motion which are associated with
the Berry curvature and side jumps give rise to a dc current quadratic in the
amplitude of the ac electric field. We demonstrate that the circular
photogalvanic effect is governed by these terms in contrast to the linear
photogalvanic effect and nonlinear I-V characteristics which are governed
mainly by the skew scattering mechanism. In addition, the Berry curvature
contribution to the magnetic-field induced photogalvanic effect is calculated.
