  For the spin Hall effect arising from strong band-structure spin-orbit
coupling, a semiclassical Boltzmann theory reasonably addressing the intriguing
disorder effect called side-jump is still absent. In this paper we describe
such a theory of which the key ingredient is the spin-current-counterpart of
the semiclassical side-jump velocity (introduced in the context of the
anomalous Hall effect). Applying this theory to spin Hall effects in a
two-dimensional electron gas with giant Rashba spin-orbit coupling, we find
largely enhanced spin Hall angle in the presence of magnetic impurities when
only the lower Rashba band is partially occupied.
