Tested on Ubuntu Desktop Versions: 8.04, 8.10, 9.04
Tested on Ubuntu Server Versions: 8.04, 8.10, 9.04

First, load lm-sensors and the required support packages:

sudo apt-get install lm-sensors i2c-tools read-edid sensord hddtemp sensors-applet

After these install, run the detection script in the terminal:

sudo sensors-detect

Answer ‘y’ to every question, including ‘yes’ to adding a section to /etc/modules.

When the script completes, restart the system.

Right click on a blank section of the panel with the system tray on it (or on whatever panel you want the applet), and select “Add to Panel…”, then add the Hardware Sensors Monitor and click on the Add button