Did find this:
"On some phones like Nokia's, it's a formula based on the IMEI Serial number of the phone. You punch in the serial number, the country you're in and the Cell phone carrier that it is locked on. ( locked on Tmobile or whatever) and then the little wizard pops out the code that you need to press onto the phone, when it asks for Subsidy password when u put a different companies sim in the phone.
On other phones, like Motorola's the command has to come from a computer thats hooked to the phone via a cable. So when you buy this software, it usually comes with a bunch of diff cables, for all the diff types of phones since they have different plug ends."