It depends on your application. You use them in the same way as a biolar opto-coupler except the output side can be wired either way around allowing it to switch alternating voltages.
To control it, all you have to do is ensure at least 1mA of DC current, maybe from a pin on your PIC flows through the LED (input) side of the device. The output is isolated and then looks like a resistor of about 16 Ohms between pins. The resistance limits their usability, if you are trying to switch more than about 100mA the heat it dissipates will damage it and they also have a maximum voltage of 60V DC (about 42V RMS AC) across them in the off state before their junctions are permanently destroyed.
So if your application is switching very small loads, they may be suitable, otherwise a mechanical relay is the better choice.
Brian.