How do I unlock my o2 locked samsung d900i to make it sim free

O2 sim Unlock

http://mobile-cellphones.blogspot.com/
You mobile is locked with o2 sim card. For that you need sim unlock code for your samsung mobile

You can generate unlock code for your mobile by imei number. Samsung unlock code is of 8 digit. My site guide you many way to unlock your samsung mobile without unlock code also.

You can unlock your phone here http://www.superunlockcodes.com/samsung-d900i/rs12wp9/
They will provide the code when you enter your imei number,you just need to select your phone model and network provider