  We explore the prospects for indirect detection of neutralino dark matter in
supersymmetric models with an extended Higgs sector (NMSSM). We compute, for
the first time, one-loop amplitudes for NMSSM neutralino pair annihilation into
two photons and two gluons, and point out that extra diagrams (with respect to
the MSSM), featuring a potentially light CP-odd Higgs boson exchange, can
strongly enhance these radiative modes. Expected signals in neutrino telescopes
due to the annihilation of relic neutralinos in the Sun and in the Earth are
evaluated, as well as the prospects of detection of a neutralino annihilation
signal in space-based gamma-ray, antiproton and positron search experiments,
and at low-energy antideuteron searches. We find that in the low mass regime
the signals from capture in the Earth are enhanced compared to the MSSM, and
that NMSSM neutralinos have a remote possibility of affecting solar dynamics.
Also, antimatter experiments are an excellent probe of galactic NMSSM dark
matter. We also find enhanced two photon decay modes that make the possibility
of the detection of a monochromatic gamma-ray line within the NMSSM more
promising than in the MSSM.
