  We present a new analysis of the Jupiter+Saturn analog system,
OGLE-2006-BLG-109Lb,c, which was the first double planet system discovered with
the gravitational microlensing method. This is the only multi-planet system
discovered by any method with measured masses for the star and both planets. In
addition to the signatures of two planets, this event also exhibits a
microlensing parallax signature and finite source effects that provide a direct
measure of the masses of the star and planets, and the expected brightness of
the host star is confirmed by Keck AO imaging, yielding masses of M_* =
0.51(+0.05-0.04) M_sun, M_b = 231+-19 M_earth, M_c = 86+-7 M_earth. The
Saturn-analog planet in this system had a planetary light curve deviation that
lasted for 11 days, and as a result, the effects of the orbital motion are
visible in the microlensing light curve. We find that four of the six orbital
parameters are tightly constrained and that a fifth parameter, the orbital
acceleration, is weakly constrained. No orbital information is available for
the Jupiter-analog planet, but its presence helps to constrain the orbital
motion of the Saturn-analog planet. Assuming co-planar orbits, we find an
orbital eccentricity of eccentricity = 0.15 (+0.17-0.10) and an orbital
inclination of i = 64 (+4-7) deg. The 95% confidence level lower limit on the
inclination of i > 49 deg. implies that this planetary system can be detected
and studied via radial velocity measurements using a telescope of >30m
aperture.
