We calculate the infrared conductivity of a stack of coupled, two-dime
nsional superconducting planes within the Fermi liquid theory of super
conductivity. We include the effects of random scattering processes an
d show that the presence of even a small concentration of resonant imp
urities, in a d-wave superconductor, has an important effect on both t
he in-plane and c-axis transport properties, which could serve as sign
atures for d-wave pairing.