It also depends on what kind of data you are reading.
If you want to get sensor/router readings through a gateway like X4, you can write a python program on the X4 to receive these data and send to your own server.
If you are looking for such kind of stuff, following links are useful, http://www.digi.com/wiki/developer/index.php/XBee_Sensors and http://www.digi.com/wiki/developer/index.php/XBee_Wall_Router