  The production of vector bosons at present and future hadron colliders will
provide a crucial test for QCD and Standard Model physics. In this paper we
improve parton shower simulations of Drell-Yan processes by implementing
matrix-element corrections to the initial-state radiation. We apply our work to
the HERWIG Monte Carlo event generator and compare our phenomenological results
with the ones obtained using the previous version of HERWIG, with resummed
calculations which we match to the exact first-order perturbative result, and
with recent Tevatron data. We also make some predictions for jet events at the
LHC.
