XATAR (Xtrasgu Applet for Temperature And Revolutions) is a simple applet for GNOME written in PyGTK to show the CPU temperature and ventilator revolutions.
Computer Temperature Monitor is a little applet for the GNOME desktop that shows the temperature of your computer CPU and disks on screen. It allows you to log temperatures to a file. You can set alarms to notify you when a tempertature is reached.
Laptop Temperature Monitor is a little applet for the GNOME desktop that shows the temperature of your CPU on screen. You can log temperatures to a file as well. Laptop Temperature Monitor is released under the terms of the GNU General Public License.
GFreqlet is a GNOME applet for Linux that not only monitors CPU frequency scaling, but also allows the end user to change the frequency or governor with just a click. It automatically detects which frequencies and governors your processor supports.