  We report observations of the Coulomb drag effect between two effectively 2-d
insulating a-Si_{1-x}Nb_{x} films. We find that there only exist a limited
range of experimental parameters over which we can measure a sizable
linear-response transresistivity (\rho_{d}). The temperature dependence of
\rho_{d} is consistent with the layers being Efros-Shklovskii Anderson
insulators provided that a 3-d density of states and a localization length
smaller than that obtained from the DC layer-conductivity are assumed.
