I found this when I was researching why my MBP runs hot lately.
http://www.conscius.de/~eidac/index.html - smcFanControl
The program allows setting the fan speeds to a higher minimum, as well as measuring the CPU temp. My laptop had a temp of 180F(!) when I installed it. Now the fans have been running at 6000RPM for a few minutes and it's down to 133F.
There is also an issue in the MacPro case design that causes hard drive bays 1 and 4 to run hotter. smcFanControl can set the minimum speed individually for each fan in the case. I've just set the hard drive fan up to 1000RPM from 500.