  We report scanning tunneling spectroscopy (STS) measurements of the gap
properties of both ceramic MgB2 and c-axis oriented epitaxial MgB2 thin films.
Both show a temperature dependent zero bias conductance peak and evidence for
two superconducting gaps. We report tunneling spectroscopy of
superconductor-insulator-superconductor (S-I-S) junctions formed in two ways in
addition to normal metal-insulator-superconductor (N-I-S) junctions. We find a
gap delta=2.3-2.8 meV, with spectral features and temperature dependence that
are consistent between S-I-S junction types. In addition, we observe evidence
of a second, larger gap, delta=7.2 meV, consistent with a proposed two-band
model.
