There are different iphone 4 unlock software available like Ultra snow,unlockphone4k, snow breeze, A proper procedure is followed for the purpose of unlocking the phone, there are a number of different iphone 4 unlock tutorial available for different software, but generic method is given in steps for unlocking the phone.
Why to unlock an iphone? There are different benefits that can be achieved after unlocking like it provides more options to the user; it gives them choices for networks which they can select according to their requirements. But the most common reason for unlocking the iphone is that because usually iPhone that are available in the market are AT&T network locked and networks other than permitted ones are not allowed. After unlocking you can use the phone anywhere in the world on the desired networks. User can choose the carrier, no need to pay extra charges for that, it means that that phone will work on any network and Prepaid SIM card can be easily used. The most significant step is to find suitable software; most of the software given on the internet is fake so one should be careful while making choice among these softwares.
Download that software, Install and start the procedure. Once the IPSW iOS download file has been done, unlocking process has been started, carefully follow all the instruction to finish the process. And remember that it is very important to Do not mess with the phone during unlocking otherwise it can be damaging to the cell phone, in case one does not do so or if the result is in the failure to follow the instructions appropriately that can outcome in making phone ineffectual.