DOBES This is the best little free app ever. I've used it for months and it has kept my macbook about 15 degrees C cooler than when it isn't running. When my CPU is taxed, Apple's controls take over and the fan speed increases according to Apple guidelines, but when it is running normally, I can set the fan at a faster speed and it keeps my system cool. Very unobtrusive, easy to turn on and off at will, a great little program.
(Version 1.2.3)