This board mates directly with the Arduino USB board and allows the Arduino to wirelessly communicate over a modified ZigBee protocol using the popular XBee module from MaxStream.
Not only is it very stylish (in bucking the trend of boring, full-coverage shields), the XBee Shield does something quite practical. It makes your Arduino / Freeduino SB wireless. Add any compatible MaxStream XBee radio module, and you'll get robust serial communication that XBee/ZigBee is famous for!
Remember, you'll need two Xbee modules to talk through, either point-to-point or mesh networking. You'll find out all about this sort of stuff when you read up on XBee. Trust us - this is very cool.
If you're in need of additional documentation or other information, check out the official Arduino.cc page.
Note: This kit does not include an XBee module.