I have a whole post dedicated to that on here somewhere...
Its MUCH easier to extend the power button wires, but some laptops have the power button soldered directly to the mainboard. So, I used a small thrust actuator from Magnetic Sensor Systems to turn my laptop on and off. Since I don't use the laptop display, I sold it on ebay. Then I drilled a hole in the top cover of the laptop and mounted the actuator in there. Works fine as long as you line up your hole correctly
