There are several vendors and solution providers for beacons. All of them support the iBeacon format. If you’re researching the hardware required to deploy a beacon solution then this report from Aislelabs might be useful.

We can’t leave out understanding the basics of the technology used in the beacon solution. A good introduction to BLE can be obtained from this introduction given by Argenox.

The foundation of beacons is based on its advertising mechanism. Beacons are effective because they allow devices to discover them without having to establish a connection with the beacon. This write-up from Argenox is a good description of the BLE advertising mechanism and how it applies to beacons.

Finally these links provide a useful overview of beacons and also provides source code that can be used to develop a beacon detector and a beacon emitter. The beacon detector should work on most Android phones but the beacon emitter may only be supported on a limited set of phones. Going forward more manufacturers may design their phones to support beacon emitters. Again adding the emitter functionallity is added complexity in the bluetooth hardware module.