SpeedFan - Hardware monitor for Windows that can access digital temperature sensors located on several 2-wire SMBus Serial Bus. Can access voltages and fan speeds and control fan speeds. Includes technical articles and docs.
CoreCtrl - CoreCtrl is a Free and Open Source GNU/Linux application that allows you to control with ease your computer hardware using application profiles.
Open Hardware Monitor - Monitors temperature sensors, fan speeds, voltages, load and clock speeds, with optional graph.
TPFanControl - TPFanControl will reduce the fan noise of your IBM/Lenovo Thinkpad.
Argus Monitor - Argus Monitor is for monitoring and analyzing the temperature and the health status of the hardware parts of the system.
NoteBook FanControl - This software detects and optionally controls speed of CPU fan of many PC-Systems.