I know how to do this in slackware but not quite sure about Ubuntu =)
i can enable ondemand with /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
my question is:
which startup script can i add a line that 'echo' > 'ondemand' into scaling_governor during boot-up?
Or which is the last script to run in ubuntu before logging in?
am using the standard 5.10 breezy.

OR: If know-one knows can someone recommend a GUI application for Gnome which will allow me to set the governor

You have to create the rc.local script.
create /etc/init.d/local, and put only this inside :

#!/bin/sh

Then, type this:
chmod 755 /etc/init.d/local
update-rc.d local start 98 2 3 4 5 .
mkdir /etc/rc.d/
ln -s /etc/init.d/local /etc/rc.d/rc.local

Hey nice one! =)
Thanks for the info.... i will give this a whirl now, makes sense.

I figured out there is a neat little gnome applet that monitors the cpu speed so i a giving this a go.. Strange thing is the value in /proc/cpuinfo does not seem to change in this build (even after activating 'ondemand' and putting a full load on the CPU.
Another strange thing is that even though 'userspace' is the default governor the cpu monitor in gnome indicates that the speed is increasing/decreasing (much the same as the conservative governor would)... there must be a userspace program controlling this.

Its all good - seems to work quite well actually

Take a look inside this folder:
/usr/src/linux/Documentation/cpu-freq
You maybe have to install kernel-sources package.