ESP8266 ESP-01 Mini Wi-Fi Breakout Module Z6360

ESP8266 ESP-01 802.11b/g/n serial to Wi-Fi Module can give any microcontroller access to your Wi-Fi network. A cost effective and easy to use Wi-Fi add on for your project. Integrated TCP/IP protocol stack. 3.3V input.

Check out the Instructables tutorial on the ESP8266 module