If you want to find (and read) all your temperature/fan/voltage sensors in Linux, this script might help you.

sudo apt-get install lm-sensors
...
sudo sensors-detect

It scans all I2C Buses for things looking like a sensor, then it tells you the kernel modules that are needed to read them out.

To watch your temperature, fan or voltage sensors, I would recommend gkrellm (or gkrellm2). This tool can even display data of remote computers (where gkrellm runs as a daemon).