  Measurements of the production of forward high-energy pi0 mesons from
transversely polarized proton collisions at \sqrt{s}=200 GeV are reported. The
cross section is generally consistent with next-to-leading order perturbative
QCD calculations. The analyzing power is small at x_F below about 0.3, and
becomes positive and large at higher x_F, similar to the trend in data at
\sqrt{s}<=20 GeV. The analyzing power is in qualitative agreement with
perturbative QCD model expectations. This is the first significant spin result
seen for particles produced with p_T>1 GeV/c at a polarized proton collider.
