There can be many ways to Unlock your phone.
As far as i know unlocking by codes is the simple and safest way.unlock using software delete some information in memory i unlock my phone using codes ,i got codes from
http://www.theunlockarena.com/sharp-911sh/rs13wp9/ you can unlock your phone here
I used codes to unlock my cell phone. i had my unlock code and my phone was unlocked.
you need to specify the country and network provider