Apple is set to start pushing what it believes will be the future of retail shopping today as iBeacon goes live in all its 254 U.S. stores. The technology, part of iOS 7, works with low-power Bluetooth transmitters and the Apple Store app to track your location within a store and provide relevant information to your phone.

Provided you give Apple permission to track you within the App Store app, standing next to an iPhone table could prompt a message asking if you'd like to upgrade your iPhone, all while checking your eligibility and whether you can get money for trading in your old phone. Another example involves a push notification alerting customers when an order is ready to be picked up alongside an order number to show the clerk.

Apple demonstrated the technology to The Associated Press this week at its busy, 24-hour Fifth Avenue store in NYC. The company has installed about 20 iBeacon transmitters at this store, some of which are simply iPhones and iPads, and each can be adjusted to specific distances so only relevant stuff comes up.

iBeacon is not limited to Apple devices or Apple retail stores. In fact, smaller scale deployments are already live at Macy's, J.C. Penney and other stores to present customers with discounts -- again, provided they have the companion app and opt-in to the service. Android devices with Bluetooth 4.0 and Android 4.3 or later are also compatible -- although not within Apple Stores, obviously, since there's no Android Apple Store app.

The transmitters inside stores (or beacons) come in a number of different formats, including small coin cell powered devices and USB sticks, and can reportedly pinpoint your location down to within 15 meters.