From ModMyiFone - Wiki
Part 2, iNdependence
This is part 2 of the OS X iPhone Unlock Guide.
Step 1
Download the 1.0.2 restore file from Apple. around 91 MB. If you are not using Safari, you will need to rename this file extension to .zip from .ipsw, and right click and uncompress. If you are in Safari, it will automatically do this for you. This file is NOT what we're upgrading/restoring to/from, it is only needed so iNdependence can use it to jailbreak.
Alternatively, just unzip the file that iTunes downloaded to ~/Library/iTunes/iPhone Software Updates/iPhone1,1_1.0.2_1C28_Restore.ipsw to somewhere convenient.
Download and run iNdependence 1.1.2a. Make sure you don't use a legacy version of iNdependance still lingering on your computer from previous activations. Drag iNdependance to your hard drive as running it inside the disk image will cause the application to not act properly. Also, make sure iTunes is located in its default install location at /Applications/iTunes.
Step 2
Click Activate iPhone.
iNdependence will ask you where you downloaded the restore file. Navigate to the folder and hit OK. Do NOT choose the file called Firmware, but rather the one containing that folder.
iNdependence will then display Waiting for jail break and your iPhone will go through a few screens, including saying Please connect to iTunes. Do not connect to iTunes, just let it run. This will take around 2-3 minutes.
Then it will say Waiting for return to jail.
You will get a Activation succeeded! message.
Congratulations, your iPhone is now activated. Lets continue topart 3 of this tudtorial.