In Connecting to Intel® Edison from Android* with Bluetooth* LE (BLE) describes a way to access BT via Arduino code but additional BT shield/kit is required.

Your robot army, controlled by Arduino and Bluetooth Open-source hardware project shrinks Arduino, adds wireless, creates awesome.

The build uses an Arduino, a Bluetooth plugin, and few chips to control the the process. The end result is a system where you can enter in a code on your phone that's transferred over Bluetooth ...

The $22 kit includes an Arduino-BLE board and 6-pin header that should be fairly broadly applicable for building Arduino-based hardware that can communicate with iOS devices.