Red Bear Labs has a ton of great code for iOS, Mac OS X, and the Arduino to browse through on their GitHub page. Included in that is the Bluetooth Shield SDK. You'll want to grab support libraries from the link on their site http://redbearlab.com/bleshield/ and drop them in your Arduino libraries folder, or import them through the Arduino IDE.



After you've got them imported, check out the Sketch here

https://github.com/scottCheezem/BlueRCSketch/tree/LED_example



it is a bare bones sketch that reads from the BLE shield one byte at a time. The First byte it reads is the pin to address, the second byte is the value (0-255) to apply to the LED at that pin.