Hereafter is an other and much simpler way.
smcFanControl allows modifying the minimal rotation speed of MacBook and Macbook Pro fans. It will only alter this, letting the machine free to accelerate in case of need.
We tested it on a MacBook Pro, where it worked perfectly well. As you will notice by yourself, the fans become very noisy above 3000 t/min. Under this limit, noise is still very acceptable.
It isn't possible to shut down the fans entirely out for security reasons, as Apple decided they should run at least at 1000 T/min since one of their SMC updates.
http://homepage.mac.com/holtmann/eidac
