everything works the same exept u have to turn 3g off. make sure when u jailbreak to match the software with the jailbreak/unlock. fo example 3.1.2 = blackrain. There isnt an unlock 4 3.1.3 yet. oh and once youre on a jailbroken iphone, NEVER update it via itunes or it will get locked again!!!
Hope i helped
Hope i helped