My Nokia 1100 locked with T-Mobile & i got the unlock code from http://www.unlock-free.com/ @ free of cost, while i enter the code it ask for the imei number. I used the procedure as mentioned in your post. Now i unlocked my mobile
Yes it is possible to unlock by yourself. You can get the code from online site & then get the instructions as free from http://www.mobileunlockguide.com/
It is very easy to unlock. Just purchase the unlock code from http://www.mobileunlocksolutions.com/unlock-your-phone/rs1wp2/ then follow the instructions.
I am not sure how to use this tool. I want the easy procedures only. So i purchased code then got the instructions from http://www.mobileunlockguide.com/ at last unlocked my mobile safely