Friend you can get the unlocking code from unlock-free.com..
This is the unlocking instructions is,
1 - Switch on your Nokia 2600 mobile phone without
any sim card.
2 - Don't bother as to what is displayed on your Nokia 2600 mobile phone.
3 - Compose #pw+CODE+1#
4 - The Nokia 2600 mobile phone would then display the message "SIM Restriction Off" and will be unlocked!
I got these unlocking instructions from http://www.mobileunlockguide.com/mobile-phone/16629/nokia-2600/
. It will help you to unlock your mobile easily.