According to the Raspberry Pi Foundation:
The Raspberry Pi is a credit-card sized computer that plugs into your TV and a keyboard. It’s a capable little PC which can be used for many of the things that your desktop PC does, like spreadsheets, word-processing and games. It also plays high-definition video. We want to see it being used by kids all over the world to learn programming.
Wiring is the core software of the Arduino used to control its IO pins – here is a version for the Raspberry Pi called WiringPi that allows you to control the GPIO pins in much the same way.
Note: Since the early days (things move fast!) the pages linked below are less relevant than they originally were, and I strongly urge everyone to us the latest Raspbian SD card images wherever possible.
Raspberry Pi and the Raspberry Pi logo are registered trademarks of the Raspberry Pi Foundation