We demonstrate electrical switching and modulation between two orthogonal polarization modes of air-post vertical-cavity surface emitting lasers with cruciform transverse cavity geometry. The continuous-wave lasing emission is switched from one polarization mode to the orthogonal mode at frequencies up to 50 MHz by a small signal modulation of the injection current. Furthermore, a polarized output signal at twice the input frequency is generated at frequencies up to 10 MHz by a large signal modulation of the injection current from below threshold to above the polarization switching transition.