A newer version of smcFanControl is available.Or, Learn More About smcFanControl
Full user review
"Does what it claims to do"
It is tiny, and shows the temperature and fan revolving.
You need to reboot - should be sufficient to restart the window manager, or just the status part.
Does what it claims, and with 0.0% to 0.4% CPU it will save battery life. Should be standard with all OS for laptops.