From what I recall in the ebay aquarium temp controller thread: pin 3 and 4 will power the controller. Pins 1 and 2 are the relay; they control power to whatever you are turning on and off. You can ignore the function control (pin 5 and 6). The temperature probe connects to pin 7 and 8.
You can check out JuanMoore's wiring diagram in the ebay temp controller thread here