  We study the influence of multiple bands on the properties of Josephson
junctions. In particular we focus on the two gap superconductor magnesium
diboride. We present a formalism to describe tunneling at a point contact
between two MgB2 electrodes generalizing the transfer-matrix approach to
multiple bands. A simple model is presented to determine the effective hopping
amplitudes between the different energy bands as a function of the
misorientation angle of the electrodes. We calculate the critical current and
the current-voltage characteristics for N-I-S and S-I-S contacts with different
orientation for junctions with both high and low transparency. We find that
interband tunneling processes become increasingly important with increasing
misorientation angle. This is reflected in certain features in the differential
tunneling conductance in both the tunneling limit as well as for multiple
Andreev reflections.
