though wiring it to a headset mike plug is a lot neater (does anyone have a circuit for this?? - I believe one needs to attenuate the signal a bit).
I was assisting in doing the setup for filming some aerobatics and it wasn't my equipment, but from what I remember it was a regular stereo headphone Y-splitter plus a long male-to-male cable which plugged directly into the cameras "mic in". No attenuation or other sound processing needed although you might need to play a bit with the volume controls.