Programming with Bluetooth protocol

Bluetooth Homepage
Bluetooth DeveloperPortal

Bluetooth wiki
Bluetooth protocols wiki
BluetoothStack wiki

BlueCode+
Stollmann’s BlueCode+ is a higher-layer stack with a wide range of possible applications that can be used both in embedded systems and in PC-based systems. It has been successfully integrated with several different Bluetooth chipsets, where it interoperates with the chip manufacturer’s lower-layer stack and with application software.

Bluetoothe Technology Basics from developer.apple.com