We present a robust, automated oscillator macromodeling technique for extracting comprehensive phase and amplitude macromodels from oscillators' SPICE circuit descriptions. The macromodels are able to correctly predict oscillator response in the presence of interference at far lower computational cost than that of full SPICE-level simulation, while retaining the simulation accuracy. We find many applications for the proposed macromodeling technique, which include injection locking prediction, fast simulation of coupled oscillating systems, and fast PLL transient simulation and jitter analysis. We demonstrate the applications on some oscillator-based systems, and compare results against full SPICE-level simulation. Experimental results show that the macromodels capture the behavior of the oscillator systems accurately, and provide speedups of over three orders of magnitude.