  We discuss the determination of polarized parton distributions from
charged-current deep-inelastic scattering experiments. We summarize the
next-to-leading order treatment of charged-current polarized structure
functions, their relation to polarized parton distributions and scale
dependence, and discuss their description by means of a next-to-leading order
evolution code. We discuss current theoretical expectations and positivity
constraints on the unmeasured C-odd combinations Delta q-Delta qbar of
polarized quark distributions, and their determination in charged-current
deep-inelastic scattering experiments. We give estimates of the expected errors
on charged-current structure functions at a future neutrino factory, and
perform a study of the accuracy in the determination of polarized parton
distributions that would be possible at such a facility. We show that these
measurements have the potential to distinguish between different theoretical
scenarios for the proton spin structure.
