How can I unlockmy phone ?

Phones that have been sold as part of a contract will often be locked to a particular network so that you're unable to switch to a new carrier at the end of your deal. However, most carriers will sell you an unlock code if you ask them. Tell them your phone's brand, model number and its IMEI code. This can be found by typing *#06# into your phone's dialler. Once you have your code, pop in your new SIM and type the code in when requested.