In the interest of at least seeing whether every little bit helps, anyone using Windows XP may want to check this link out - http://www.localcooling.com/?www.reghardware.co.uk

The article link is http://www.reghardware.co.uk/2006/11/30/pc_cooling_app/

And since this is not Slashdot or groklaw, no comments about anyone's choice of operating system.

Cute idea, I will put a link on my blog.
you don't need it.
just make sure you install the power management drivers in windows(cool 'n' quiet for amd cpu's(amd64 and newer) powernow(for older k7's with power management) intel's i think is called speedstep). then go to your control pannel -> power management -> and from the drop down menu choose 'minimal power management'.
in linux it's simpler.
su
to root 'su'
go to
/usr/src/linux
(symlink to the current kernel tree)
type
make menuconfig
then go to the following.
Power Management Options
         ACPI --->

and then select the following (x = * for built in)

[x]ac-adaptor
[x]fan
[x]button
[x]video
[x]processor
[x]thermal zone

if your also on a laptop also select 'battery, ac adapter, and dock'.
then go to

power management options
    cpu frequency scaling--->

before selecting the following.

[x] Cpu Frequency scaling
[x]    Default cpufreq governer (userspace) -->
[x]    'Performance' Governor
[x]    'Powersave' Governor
[x]    'Conservative' Governor (choose this instead of 'On-demand because it's a smoother transition between states)

under this is the list of cpu drivers for frequency scaling.
choose the following for amd64 based cpu's

[x] Amd Opteron/Athlon64 PowerNow!

or for intel's cpu's

[x] Intel Enhanced SpeedStep

there are other drivers there depending on the arch and whether the system your running is a 32bit or 64bit system.
from then all you have to do is install your favorite cpu freq manager and then tell it what state you want as default(most likely conservative) and forget it :)

for those of you who are wondering why i called the linux method easier, you do not need to go searching for the driver on a cd or on the web before installing it's already in the kernel.

Well, the Register article link pretty much makes the same point that it isn't really anything revolutionary, just that it is fairly simple, which is better than nothing.

Personally, I use openSUSE, and power management is pretty simple from its 'Control Center,' though real tweaking is always done in the conf files - it is just that SUSE has always had the very unfortunate habit of rewriting them anywasy after the tweaking - YAST is a very mixed blessing.

One of the things that makes this application a bit more interesting is the social aspect - most 'marketing' hinges on higher consumption, while this makes conservation the goal.

Of course, making sure that the PC, monitor, and peripherals are truly shutdown to no electric use is a hardware problem. I use a powerstrip with an off switch. The draw of turned off equipment is easily 20W and higher.

personally i would recommend you move away from opensuse due to the recent deal novell made with ms. don't want to be on the wrong side of a ip war. but thats a different topic.
i have tried to explain it to other people to use a power strip to really shut everything off.. though they stop doing it as soon as they find out that when they do that and turn the power back on and find they have to wait 20 seconds to a minute before they are able to turn on their lcd screens they ignore me..