Do I need to setup my speaker for every iDevice or computer that I will use my G-17 and AirPlay from?

No, the setup of your new Klipsch G-17 Air speaker is a one-time process. Once you finish the setup, your speaker is available from any iDevice or computer operating on the same WiFi network as your speaker. Just look for the AirPlay icon in iTunes 10.1 or later, your iPod player or any AirPlay compatible application.