Hi,
In some situations you will need to be able to provide the MAC address of your phone in order to gain access to a WIFI network, or to access a Bluetooth compatiable printer.
Here is how……
TO find the MAC Address (Bluetooth device addresses). To find the unique address of your device, enter the code *#2820# in the standby mode.
To check the unique Media Access Control (MAC) address that identifies your device, enter *#62209526# in the standby mode.
I hope this is of use !
Macbuckley
N91-MAC 
Thank you very much
Thanks, been looking for this….
how can i change BT or MAC address ?
Your Research on Nokia N91 is intersesting and easy to understand.Even you wrote the prevention in carrying out the operations.Thanks for making me Smile