If you have bought an ATT phone from a service provider the mobile would be locked to their network carrier services. It will not work on any other GSM sim card. This is really like a trap as you cannot switch to any other network service provider offering better deals in the market. The roaming charges are also going to be expensive as you cannot switch over to a local network carrier when you are traveling abroad. This is the reason that many wish to have their ATT sim unlocked. There are two solutions for you where you can either approach your present network carrier or a third party phone unlocking shop to avail your ATT sim unlock code. While the former is quite expensive the later offers you a quick solution within affordable prices to unlock your mobile permanently. To unlock ATT SIM you have to send the IMEI number of your mobile and get the code from the phone unlocking shop along with the instructions on how to use it to have your phone unlocked permanently.
 

 
You can contact the phone unlocking shop to unlock any model phone that is contracted or out of contract with various network carrier services. You can SIM unlock Samsung edge by finding the IMEI code on pressing *#06# or look beneath the battery sticker to send the number and the present phone model and carrier service to the online code unlock shop. They shall send you the factory unlock code along with instructions on how to use it in your phone. You don’t need to have any technical knowledge or skills to Sim unlock Samsung edge. You first need to switch on your phone without a SIM. Then compose #PW+CODE+1#. The letter P appears and you have to press the star button quickly for three times. The same for the letter W and + where you have to press the star button and have your phone unlocked instantly.
 

 
To SIM unlock Blackberry you need to send across the 15 digit IMEI number, model number of the phone and the network carrier details to the online phone unlocking services. They shall send back the code along with instructions on how to use it in your blackberry phone. You first need to turn off all the wireless connections of the mobile and go to options icon shown on the device.  Then select device and advanced system settings. You shall then have to click go to settings and enter mepd and the letters mep2. The device will ask to enter network mep code and you have to enter the given code to have your phone unlocked permanently. The phone unlocking services charges their fees based on the phone model and the network carrier services but with onetime fee you can have a legal and permanently unlocked phone to switch on to any sim card of your choice.