How to: Infrared LED Communication

There are plenty of methods to allow your gadgets to communicate wirelessly: Bluetooth, radio frequencies, and of course, IR LEDs just to name a few.Â� Today we’ll teach you how to use IR LEDs as communication devices for your projects. Infrared light is invisible to the human eye, but can be picked up by cameras.

This tutorial has some simple circuits and explanations.
Johnny Lee has plenty of fantastic videos using IR LEDs for communication using the WiiMote.
Each button on a universal remote emits a unique, rapid pulsation of IR light. You can capture these codes and use them to control an Arduino. “If code 100111001 then blink pin 12.”
Further info can also be found here and here too.