You don't need to unlock it. You need the MSL number and you can get that by dialing ##000000. You will need to give that number to Cricket or MetroPCS as they generally allow other CDMA devices on their networks. However, I don't believe they offer BlackBerry service.
Good luck trying to get free service.
__________________ The difference between stupidity and genius is that genius has its limits. When you take things for granted, the things you are granted, get taken. Even a mosquito doesn't get a pat on the back until it starts to work. Too many people miss the silver lining because they're expecting gold. [BES 5.0.3 / GroupWise 2012 HP2]