Hi,
You may have heard that the iPhone 4S supports BLE. It most certainly does. In fact, app developers have access to the GATT interface through the new Core Bluetooth API. We've put together a demo of the iPhone 4S communicating with the keyfob from the CC2540DK-MINI here: http://www.youtube.com/watch?v=c_WtPGHek3Y.
This is what we have been waiting for for a long time: It is finally possible to develop BLE apps on a major smartphone!
Best regards,
Karl