I recently replaced my PowerBook G4 with a new (2/2008) MacBook Pro 2.4GHz with the latest "Penryn" processor. My biggest complaint was that in a quiet room the MacBook Pro fans could be easily heard, where my PowerBook was dead quiet. I tried smcFanControl but as other bloggers stated, it doesn't allow one to DECREASE fan speed. Your stuck starting at the Apple Default of 2000 rpm. Well, the Penryn is much cooler than previous processors. I tried a different utility called "Fan Control 1.2" and it allows decreasing the fan speed but also you can decrease the set point for increasing the speed. I'll tell ya, even going down to 1800 rpm made big difference, I'm currently set at 1400 rpm and all you can hear is the hard drive now. When I start "pushing" the processor the fans slowly speed up and try to keep the temp around 50˚C. Haven't gone much above 55˚C or 2500 rpm. Of course, if you choose, Fan Control allows you to do what smcFanControl does ie set the fan rpm higher (up to 3500 rpm). I'm sure with the decreased fan setting we could get slightly better battery life. Now if I can only get the voltage or processor speed to adjust down I can max out battery life.