  Hundreds of gravitational microlensing events have now been detected towards
the Galactic bulge, with many more to come. The detection of fine structure in
these events has been theorized to be an excellent way to discover extra-solar
planetary systems along the line-of-sight to the Galactic center. We show that
by focusing on high magnification events the probability of detecting planets
of Jupiter mass or greater in the lensing zone (.6 -1.6 $R_E$) is nearly 100%,
with the probability remaining high down to Saturn masses and substantial even
at 10 Earth masses. This high probability allows a nearly definitive statement
to made about the existence of lensing zone planets in each such system that
undergoes high magnification. One might expect lightcurve deviations caused by
the source passing near the small primary lens caustic to be small due to the
large distance of the perturbing planet, but this effect is overcome by the
high magnification. High magnification events are relatively rare (e.g. $\sim
1/20$th of events have peak magnifications greater than 20), but they occur
regularly and the peak can be predicted in advance, allowing extra-solar planet
detection with a relatively small use of resources over a relatively small
amount of time.
