Arduino 433mhz RF Network Controller
In order to use the sketch, you will need to have an Arduino with a 433mhz sender connected to pin 10 (by default, but configurable in the sketch).
The sketch also makes use of an "Arduino Ethernet Shield v1.1" using the ENC28J60 chipset. These are about the cheapest way of connecting an Arduino to ethernet and you can pick up the shield for less than $10 (€8) delivered from Deal Extreme.
I'm using the Jee Labs library, available here; https://github.com/jcw/ethercard
The script also makes use of the RCSwitch library, available here; https://code.google.com/p/rc-switch/
In order to call the Arduino and ask it to change the status of a connected device, you simply need to send a UDP packet to the Arduino with the command embedded. A simple way to do this from a Linux command line is using ncat, which you'll likely already have installed.
Example to turn my heating off;
echo heat:0:|ncat -u 192.168.1.99 1337 --send-only
"--send-only" is needed so the command exits back to the command line. You'll also notice I added an additional ":" at the end of the command to ensure the Arduino doesn't parse the string as having a linebreak at the end.