  We present the general formalism for studying CP-violating phenomena in the
production,mixing and decay of a coupled system of CP-violating neutral Higgs
bosons at high-energy colliders. Considering the Minimal Supersymmetric
Standard Model (MSSM) Higgs sector in which CP violation is radiatively induced
by phases of the soft supersymmetry-breaking parameters, we apply our formalism
to neutral Higgs production via {\bar b}b, gg and W^+ W^- collisions and their
subsequent decays into tau^+ tau^- pairs at the LHC. We discuss CP asymmetries
in the longitudinal polarizations of tau^+ tau^- pairs based on a scenario in
which all neutral Higgs bosons are nearly degenerate and the CP-violating
signatures are resonantly enhanced.
