The shield allows to easily mount one XBee board and all the components to get it up and running. When plugged on an Arduino NG board without the processor it will act as a USB to XBee converter becoming an interface for all your XBee enabled devices to a computer.
Board's version 0001 is beta and under test by the team these days, but it should be launched soon as a DIY kit with all the components included. If you are interested in this design, please let us know about your interest on this forum thread. The more boards we manufacture at once, the cheaper the design will become.