Distinguishing Between Models with Extra Gauge Bosons at the ILC

Extra neutral gauge bosons arise in many extensions of the Standard Model. If one were to be discovered it would be necessary to measure its properties so that we could understand its origins. In this report we find that Z' couplings can be measured at the ILC precisely enough to distinguish between models up to a Z' mass of 2-3 TeV. An important ingredient in these measurements is polarization of the e^- and to a lesser extent e^+ beams. b and c-quark tagging would also give important additional information.