I used "Blackra1n". It works for either MAC or PC, doesn't matter. It's simple, just download it and when the iPhone is connected open the program and click "make it ra1n" then it will JailBreak your iPhone.
1. Once the iPhone boots up again, go in the iPhone and you should have an app called "Blackra1n".
2. click each one of the options (I believe there is Cydia, Rock, and the unlock whatever it is called)
3. Let the iPhone do its thing when downloading those things and once it reboots it will be unlocked and JailBroken.
4. Put in your SIM and you are ready to go!
And if you have any problems after it is Unlocked just connect your iPhone to your computer and click "make it rain" and everything will be back to normal without ruining anything or deleting any information.
Wow, I should get paid for advertising.
Hopefully this helps
GAGA FOR LIFE