This is the WiFi module used in LinkSprite's CuHead Wifi shield, Diamondback Wifi Arduino, Redback WiFi Arduino.
WIFI TRANSCEIVER w/PCB ANTENNA
Microchip Technology MRF24WB0MA / MRF24WB0MB Wi-Fi® Transceiver Modules
The Microchip Technology MRF24WB0MA and MRF24WB0MB2.4GHz transceiver modules feature extremely low receive currents for longer battery life. These Microchip Technology devices are the first certified embedded Wi-Fi® modules following the ZeroG acquisition. The IEEE 802.11 module firmware has an easy-to-use API driver interface to the Microchip free TCP/IP Protocol stack and to Microchip PIC® microcontrollers. The low-power MRF24WB0MAand MRF24WB0MB embedded Wi-Fi modules remove the complexity and cost of developing RF circuitry and obtaining agency certification. These Microchip Technology RF transceiver modules are optimized for use in a variety of applications, including utility and smart energy, consumer electronics, industrial controls, remote device management, retail, and medical / fitness / healthcare.