  The coupling of two s-wave superconductors through a small magnetic dot is
discussed. Assuming that the dot charging energy is small compared to the
superconducting gap, $E_c\ll \Delta$, and that the moment of the dot is
classical, we develop a simple theory of transport through the dot. The
presence of the magnetic dot will position Andreev bound states within the
superconducting gap at energies tunable with the magnetic properties of the
dot. Studying the Josephson coupling it is shown that the constructed junction
can be tuned from a "0" to a "$\pi$"-junction via a degenerate two-level state
either by changing the magnetic moment of the dot or by changing temperature.
Furthermore, it is shown that details of the magnetic dot can be extracted from
the sub-harmonic structure in the current-voltage characteristics of the
junction.
