1) You would need to obtain a bluetooth 4.0 BLE (Bluetooth Low Energy) transmitter/receiver chipset to attach to/install in your MacBook.
This would allow you to transmit the beacon signal.
2) You would need to create or purchase software that could use the chipset appropriately.
This would allow you to recognize the presence of nearby beacon-enabled devices, such as the new iPhones, and interact with them appropriately.
Here's a site that explains more about iBeacons and BLE with some good example videos (actually linked to from 'iBeacon' in the original question):
Apple's iBeacons explained - What it is and why it mtters - Pocket-lint
Here is a link to a company selling BLE transmitter/receivers for use commercially (mentioned in the article above). This site also provides an overview as to how the technology works:
Estimote Beacons - real world context for your apps
This site gives details on BLE:
Low Energy | Bluetooth Technology Website
Then I'd say, put on your engineering hat and start searching for chipsets and software solutions!
Another name for BLE is Bluetooth Smart. Search for hardware and/or software that is Bluetooth Smart (does BLE only) or Bluetooth Smart Ready (does both legacy bluetooth and BLE). Some lists are on the Bluetooth Technology Website (same as above), and a Google search brings up a few apps that have already been created.
Another search brings up a document for Apple developers:
Apple's Bluetooth Design Guidelines (from their developer center)
and a rapid development tool for Apple developers (from bluetooth.org):
Apple Developers | Bluetooth Development Portal