You are probably looking for the product manual at:
or
http://www.digi.com/products/wireless/zigbee-mesh/xbee-series2-moduledocs.jsp
I'll leave it up to you as to whether you have series 2 or series 1, but the "Command Reference Tables" and "Command Descriptions" are the sections you are looking for.
One neat feature would be enabling remote XBee analog data aquisition. You could then have an Arduino with attached XBee and a remote standalone XBee with attached sensors.