The Beta release of our BLE HCI library, with BLE Central support, is now available on our GitHub page. We provide codes for Arduino and Python (tested on Raspberry Pi, Mac OS X and Windows PC). Please note that this library is still a work in progress, not all HCI commands and events have been implemented. Kindly post your bug reports and comments on our forum.
David Edwin, Senior Software Architect at Nordic Semiconductor, has developed a "nRF8001 SDK for Arduino" which is compatible with BLE Shield. He conducted a webinar "Enabling Bluetooth Low Energy on Arduino Platform using Nordic nRF8001 module" in which he goes in great details on how to develop BLE services using Nordic nRF8001. The SDK contains working template for Heart Rate, HID and UART services, you can download his SDK and ask questions about it on the Bluetooth Development Forum. You will find detailed instructions on how to get your BLE Shield setup in the Q&A section.
Update: You can now post questions about Nordic nRF8001 SDK for Arduino on our support forum.