  We investigate the role of the transverse spin dependence in Drell Yan lepton
pair production to NLO in QCD at parton level. In our analysis we deal with the
large $p_T$ distributions. We give very compact expressions for the virtual
$O(\alpha_s^2)$ corrections to the cross section and show that the
singularities factorize. The study is performed in the $\bar{MS}$ scheme in
Dimensional Regularization, and with the t'Hooft-Veltman prescription for
$\gamma_5$. A discussion of the structure of the real emissions is included,
and detailed methods for the study of these contributions are formulated.
