First, I used an Arduino Uno board for the core of this project.

For WiFi connectivity, I used an Adafruit CC3000 breakout board. You could also use an Adafruit CC3000 WiFi shield, the code would be exactly the same.

For the power switch itself, I used a powerswitch tail 2 kit, which allows to easily make the connections between the device you want to control and the mains elecricity. Then, it is really easy to control the device using a microcontroller board like Arduino. This is a picture of the kit I used (in its EU version on the picture): 

Finally, I used a breadboard and some jumper wires to make the different electrical connections.

On the software side, you need to have the latest version of the Arduino IDE installed on your computer.

You will also need to have Node.js installed on your computer, to run the interface on your computer. You can download it by going at the following address:

http://nodejs.org/

You will also need the aREST library for Arduino which you can find at the following link:

https://github.com/marcoschwartz/aREST

This project also requires having the CC3000 chip library:

https://github.com/adafruit/Adafruit_CC3000_Library

And the CC3000 mDNS library:

https://github.com/adafruit/CC3000_MDNS

To install a given Arduino library, simply extract the folder in your Arduino /libraries folder (or create this folder if it doesn’t exist yet).