  Temperature dependent optical conductivities and DC resistivity of c-axis
oriented superconducting (Tc = 39.6 K) MgB2 films (~ 450 nm) have been
measured. The normal state ab-plane optical conductivities can be described by
the Drude model with a temperature independent Drude plasma frequency of
\omega_{p,D}=13,600 +/- 100 cm-1 or 1.68 +/- 0.01 eV. The normal state
resistivity is fitted by the Bloch-Gruneisen formula with an electron-phonon
coupling constant \lambda_{tr} = 0.13 +/- 0.02. The optical conductivity
spectra below T_c of these films suggest that MgB2 is a multi-gap
superconductor.
