Once you've got the basic XBee API Frame types covered in code it's quite easy to accomplish, cause much of what is needed is already there, in your own Domotica system

You can read about it here:
http://blog.hekkers.net/2010/07/05/zigb ... onitoring/
And there's a webpage showing some values being monitored:
http://www.hekkers.net/domotica/ZigbeeNetwork.aspx