Looking for a way to read an XBee Address or ID using an Arduino so that I can uniquely identify where a string is originating from without having to have a separate program installed on each Arduino.
You could upload a sketch to the Arduino that stores a string in EEPROM. Change the string for each Arduino. Then, upload the sketch that the Arduino should run for real, that gets the string from EEPROM, and prepends it to any string sent.