I'm just going to copy and paste from a site...
What is GSM Remote Unlocking?
GSM unlocking removes the sim lock on your phone, allowing you to use one phone on any GSM network. Some GSM networks include AT&T, T-Mobile, Rogers, Fido, Vodafone etc. All you need to do is provide the serial number (IMEI), and wait for a representative to e-mail you with instructions and a code to eliminate the lock. This service is provided remotely. Anyone can do it!
Who is it for?
Anyone and everyone! This gives you the freedom to travel without having to worry about buying or renting a phone in a foreign country. You simply buy a pay as you go sim card and insert it into your unlocked phone. Not only will it save you money, but if you decide to sell your phone, it will increase the value of your phone significantly!
Is it safe? Is it illegal? What if my provider finds out?
Yes it is safe. All of our codes come straight from the manufacturer or provider. It is not illegal to unlock your phone. Infact, it is illegal to have your phone locked in some countries. We have never had a complaint about someone's phone malfunctioning from unlocking by code.