Since v1.4.0 Locative supports the use of iBeacons as Geofences.
The feature set is pretty the same as with geographical Geofences, this App can be used with any Bluetooth 4.0 (LE) iDevice to advertise as am iBeacon.
When using Locative, the iBeacons UUID must be entered when adding an iBeacon, the Sample App's UUID defaults to 954FBC91-620E-4B5A-86F7-1F31A0054194
To use the Sample project, simply check out this Repo open the GFBeacon.xcodeproj and hit run.
For more info about Locative check out http://locative.io or get it in the App Store at http://get.locative.io.
There's also another neat little feature which will gain more attention in the near future. Locative features a Geofence-Logging as-a-service at https://my.locative.io. So check it out and grab yourself an account ;-)