This circuit is what I am going to use to match transistors for my Open OTA project. It is pretty basic. The two transistors are connected up as a differential amplifier. The two opamps amplify difference between the collectors of the two transistors which is proportional to the difference in current flowing though the transistors. A voltmeter is connected to the outputs of the two opamps. You are going to want to match the resistors in the collectors of the DUT transistors so that there will be as little error as possible. You will also want to match the feedback resistors in the opamp circuit as well.

Another keen feature is a switch that switches the collector current from 0.5 mA to 0.5uA. This is important because you want the transistors matched over a wide range of currents to keep the control voltage feed threw to a minimum.