Programming Arduino Wirelessly
The following example demonstrates how to build a complete wireless solution for uploading code to a remote Arduino microcontroller using a couple of XBee radios, and a handy function for accomplishing wireless resets.The Arduino system offers an easy and open-source method for programming microcontrollers. Normally this means using a serial cable or USB cable attached directly to the microcontroller project.
   Programming Arduino Wirelessly
For more detail Programming Arduino Wirelessly website
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