Source: http://embraceubuntu.com/2005/11/04/enabling-cpu-frequency-scaling/
In addition, to add the option to manually select the speed via the CPU Frequency Scaling Monitor panel, you'll need to enter the following command in case you miss it on the source:
In addition, to add the option to manually select the speed via the CPU Frequency Scaling Monitor panel, you'll need to enter the following command in case you miss it on the source:
$sudo chmod +s /usr/bin/cpufreq-selector