Well I have not soldered one in, but I have compared to a standard header and the pin spacing is identical and will plug into a connector that takes a standard header so I am positive it will go right into a three pin header spot.
I had not thought about pinout but I just ohmed one and the center pin IS switched, BUT the slider is oposite of the pins that are connected. SO if you switch it to the right, the left and center pins are connected, and if you switch it to the left, the right and center pins are connected. The outer pins do not connect in either switch position. The way to think of it is that where you see the gray part of the housing indicates what is selected.
So in the picture above, the switch is left so the right pin is connected to the center pin.
Only a little confusing, but still works.
Kirk