The Arduino WiFi Shield connects your Arduino Uno/Freeduino to the internet wirelessly. Connect it to your wireless network by following a few simple instructions and start controlling your world remotely through the internet.
Previously there were a select few ways to connect your Arduino to a wireless network but now it's officially available from Arduino themselves! They have now released the Arduino WiFi Shield! As always with Arduino, every element of the WiFi shield – hardware, software and documentation – is freely available and open-source. This means you can learn exactly how it's made and use its design as the starting point for your own circuits.
The shield contains a number of informational LEDs:
Check out the reference page of the WiFi library to understand how the shield can easily provide an internet connection to your Arduino board. The WiFi Shield communicates with Arduino using the SPI bus (through the ICSP header), so is compatible with any of the boards that have this type of bus. This version of WiFi shield have an integrated antenna on the PCB, what you have to do is just connect the shield to the Arduino and you don't have to worry about finding an external antenna. The back portion of the board even sticks out a little to get the antenna a stronger signal when other shields are stacked above it. If you want to have a closer look at this board we advice you to visit the official Arduino WiFi Shield page in the Hardware Section.