The other version was pretty damned confusing and could lead to people mixing up the number ordering. So now, I present the latest version of fanctl!

Xbox root # fanctl
Fanctl by ShALLaX (c). Run: 'fanctl --help' for usage

Sensor: CPU
Current temperature: 36 °C
Low temperature limit: 40 °C
High temperature limit: 50 °C
Low speed: 20% and locked
Mid speed: 74%
High speed: 100%

Old speed: 20%
Setting LOW speed and locked

There is also now a nice, and neatly formatted help page (although the formatting doesnt transfer into phpnuke). The switches are now logical and simple and can be invoked in any order. Furthermore, if some switches are omitted from the command line, default values will now be automatically selected as shown in the following quote:

Fanctl by ShALLaX (c)
This tool allows you to set the Xbox's fan speed.

Simple usage:
-f, --setspeed X - Set fan to X% speed (20 > 100)
Use this switch on its own!

Advanced usage:
-l, --lowtemp X - Set low temperature limit to X (0 > 999) - default: 40
-h, --hightemp X - Set high temperature limit to X (1 > 1000) - default: 50
-x, --lowspeed X - Set low fan speed to X% (20 > 100) - default: 20
-y, --midspeed X - Set mid fan speed to X% (20 > 100) - default: 75
-z, --highspeed X - Set high fan speed to X% (20 > 100) - default: 100
-s, --sensor X - Set the sensor to: CPU, board - default: CPU
-t, --scale X - Set the temperature scale to: C, F - default: C

Other:
-?, --help - This screen

Rules:
Key: <=: less than, <>: between, >= above
If the current temperature is <= the low temp limit - LOWSPEED is selected.
If the current temperature is <> limits - MIDSPEED is selected.
If the current temperature is >= the high temp limit - HIGHSPEED is selected.

Again, this has been extensively tested for logic holes and it all seems fine. The 20-100% fan speed safety measure is still enforced, and if the fan speed hits 20%, the controls will be locked (stops other potentially malicious programs from messing with the fan speed, so long as they dont unlock the register first!).

Follow the normal proceedure to upgrade: 'magic fix monitors && magic'

Note that youll need to download the updated loadfan/ loadfanled scripts (if you are using them). The new fanctl makes managing these scripts so much easier - see for yourself!
Enjoy!