This new version corrects the pin out for the GPX and RESET pins. The SparkFun USB Host Shield contains all of the digital logic and analog circuitry necessary to implement a full-speed USB peripheral/host controller with your Arduino. This means you could use your Arduino to interface with and control any USB slave device - thumbdrives, digital cameras, bluetooth dongles, and much more!
The Host Shield takes its power from the ‘Vin’ pin on your Arduino. Power from that pin is regulated to both 5V and 3.3V on the shield. All SPI signals are sent through a hex converter to step them down to 3.3V.