  We examine the spin-dependence of b-quark production at large transverse
momentum in polarized proton-proton collisions. The leading-order (LO) 2 -> 2
subprocesses, g + g -> Q + Q-bar and q+ q-bar -> Q + Q-bar have a large
`analyzing power', as measured by the average spin-spin asymmetry <a-hat_{LL}>,
at large p_T, approaching -100%. The contributions from next-to-leading order
(NLO) 2 -> 3 processes are also discussed and found to be dominated at large
transverse momentum by subprocesses with a large and positive partonic level
spin asymmetry leading to strong cancellations with the LO predictions. The
results suggest that b-quark production might constitute an interesting test of
the spin-dependence of NLO QCD but they also point up the importance of a full
calculation of the complete O(\alpha_S^3) spin-dependent corrections for a
successful extraction of the polarized gluon distribution. Similarities to
gluino pair production are also briefly discussed.
