Here are some links

http://elasticsheep.com/2012/06/bluetooth-module-firmware-dump/

http://elasticsheep.com/2012/06/bluetooth-module-parallel-spi-interface/
...

You can use hc-05 board directly with voltage level converter. It translate 3.3 ttl level from hc-05 to 5v ttl level at ALDL port. I already tried that with good results.
The main problem is HC-05...