The XBee modules can be configured in two ways: Transparent Mode (AT) and API Mode (API). In AT mode you are limited to point-to-point communication between two XBees. In API mode, we can trivally send and receive from both the COORDINATOR and many many XBees out in the world. Additionally, API mode will expose a variety of additional information encoded in each packet.
In a point-to-multipoint wireless configuration (see picture 1), multiple nodes (Router/End Devices) pictured in blue, send to and receive from a central coordinator (red).
Andrew Rapp wrote a great XBee Java API which can be found here: http://code.google.com/p/xbee-api/
Andrew also provides detailed instructions for integrating the XBee API with the popular IDE Eclipse. For my project (and for unknown reasons) I decided on using the Swing JAVA GUI library which, for me, was a little easier to develop for using NetBeans. Therefore, I will also provided instructions on how to setup the XBee JAVA API using Netbeans. But first we need configure the firmware on the XBee.