  Certain modern theories of gravity predict that antimatter will fall
differently than matter in the Earth's gravitational field. However, no
experimental tests of gravity on antimatter exist and all conclusions drawn
from experiments on matter depend, at some level, on a specific model. We have
proposed a direct measurement that would compare the gravitational acceleration
of antiprotons to that of negatively charged hydrogen ions. Substantial
progress towards the development of this experiment has been achieved. Based on
our work a number of alternative proposals for measuring ``$g$" on both charged
and neutral antimatter have been made. We summarize the present status of our
experiment and also discuss the steps that would be necessary to produce
antihydrogen in an environment suitable for gravity measurements.
