  The results of a recent calculation of the QCD corrections to the
longitudinally polarized Drell-Yan process are summarized. In addition to the
parity conserving double spin asymmetry which is already accessible in the
Drell-Yan production of lepton pairs at fixed target energies, we consider
parity violating single spin asymmetries appearing only in the production of
massive vector bosons at polarized hadron colliders. The prospects for
extracting polarized quark distributions from asymmetries in vector boson
production at RHIC are briefly discussed.
