I am wondering this because i want to make a program that takes the fan speeds, and then maps that value between 160 and 255. After that it is going to send that value to my arduino to adjust the external fan that i have so it changes it's speed proportianally  to my macbook pro's speed. I have everything done except getting the fan speed of my macbook pro which is going to be displayed in the window and the speed of the external fan. I am running lion if that helps any