  We report the observation of two gaps in the superconductor
SmFeAsO$_{0.9}$F$_{0.1}$ (F-SmFeAsO) with $T_c=51.5K$ as measured by
point-contact spectroscopy. Both gaps decrease with temperature and vanish at
$T_c$ and the temperature dependence of the gaps are described by the
theoretical prediction of the Bardeen-Cooper-Schrieffer (BCS) theory. A
zero-bias conductance peak (ZBCP) was observed, indicating the presence of
Andreev bound states at the surface of F-SmFeAsO. Our results strongly suggest
an unconventional nodal superconductivity with multiple gaps in F-SmFeAsO.
