If you bought your phone from somewhere other than a mobile provider, it might not need unlocking. It's easy to find out simply by inserting a SIM card from another provider. If the phone works as normal then it isn't locked. If it displays a message similar to 'incompatible SIM', 'enter subsidy PIN' or 'enter network unlock code', then it is locked. Then you'll need to find your IMEI (International Mobile Station Equipment Identity) number. The IMEI number of your handset is unique and will be required by unlocking services. To find it, type *#06# into your phone. This will display the 15-digit number. It's a good idea to keep a note of this number to speed the process along.