  In this paper we study the cross section at leading order in $1/Q$ for
polarized Drell-Yan scattering at measured lepton-pair transverse momentum
$Q_T$. We find that for a hadron with spin $1/2$ the quark content at leading
order is described by six distribution functions for each flavor, which depend
on both the lightcone momentum fraction $x$, and the quark transverse momentum
$\bbox{k}_T^2$. These functions are illustrated for a free-quark ensemble. The
cross sections for both longitudinal and transverse polarizations are expressed
in terms of convolution integrals over the distribution functions.
