To unlock your mobile phone you should change the software inside your mobilephone memmory
You can also unlock your mobilephone by entering some codes into your mobile phone.
But i am not sure that unlock codes will work.
I have even heard of unlocking devices,but they are of high price.
Someetimes your mobile operator will block your phone to acess only a single network.This is done to prevent loss of customers and to avoid users change there SIM card easily.
Locking of network is also possible in CDMA Handsets.
There are software for unlocking mobilephones.
But to use software to Unlock your phone you should have Data Cable.
Thank You...