Programming the Arduino BT WT11 module.
The following schematic is a simple parallel port programmer for the BlueGiga bluetooth module on the Arduino BT. It is a bit simpler than the suggested programmer shown on the BlueGiga support pages. It also uses components that are more readily available. Warning! On the shematic, the supply pins of the cd4050 are reversed! Correctly: pin1 is vcc and pin8 is gnd
You may need to use a WT11 programmer if for some reason the WT11 stops responding to the serial commands from the ATMega168. I had this problem when attempting to change the serial communication speed. The only way to get out of this condition is to transfer fresh firmware to the WT11. Perhaps, you might just want to make sure your WT11 is using the latest firmware.
You can use BlueGiga tools: PSTool & iWRAP Update Client. Register with BlueGiga to download these tools.