All the users who have forgotten their Security/Lock Codes need not to worry. You just need to know your IMEI (International Mobile Equipment Identity) number.

To check your IMEI number, type *#06# on the main screen. This number can also be found on the backside of the handset. Just remove the battery

You can visit a site which will calculate the Master Code of your phone. This code can be used to change your present Lock/Security code.

http://www.nokialockcode.com
(for )
Note :
1. Lock/Security Code is not the PIN Code.
2. If you want to remove the Service Provider Lock, then this is the wrong thread.
3. The Master Codes are only for DCT-3 and DCT-4 phones.