How to configure powernowd
powernowd originally was only written for AMD CPUs which support PowerNow! technology, but it supports other CPUs as well.
Make sure you have loaded the necessary kernel modules. (See How to make use of Dynamic Frequency Scaling)
On Debian you can do this with:
# apt-get install powernowd
Use the sys interface to set the min and max speed:
# echo 825000 >/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
# echo 2200000 >/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
# /etc/init.d/powernowd start
In Debian you may specify different options for powernowd in /etc/default/powernowd. This file will be loaded by the init script /etc/init.d/powernowd.