  Acceleration of polarized protons in the Relativistic Heavy Ion Collider
(RHIC) provides a unique tool to study the spin structure of the nucleon. We
give a brief overview of the PHENIX program to investigate the unknown gluon
and flavor decomposed sea quark polarization in the proton, utilizing polarized
proton collisions at RHIC. We report first results from the PHENIX experiment
on transverse single-spin asymmetry in pi0 and charged hadron production and
longitudinal double-spin asymmetry in pi0 production, at mid-rapidity.
