david schultz dot org(dot com was taken)

These instructions are from iClarified who seems to be getting slammed at the moment (this was just released an hour ago as i write this. These 8 steps took about 30 seconds->1 minute to complete (!!!), and i can confirm everything works great. I was able to replace my Rogers SIM with a RoamForce World Sim and make calls immediately. Having said that, proceed at your own risk:

These are instructions on how to jailbreak and unlock your iPhone 3G and 3GS using BlackRa1n and BlackSn0w for Mac.

These instructions will work with the latest 3.1.2 firmware, the 05.11.07 baseband, and iPhones which require hactivation.

For those with a new iPhone 3GS (updated Bootrom), BlackRa1n only supports a tethered jailbreak. This means that once jailbroken you should not let your battery die. If it does die you will need to reconnect it to the computer and use BlackRa1n to boot it.

Before continuing make sure you are on the 05.11.07 baseband by following this tutorial. If you are not please update your firmware to 3.1.2 using iTunes before continuing.

Step One
Open your web browser of choice and navigate to http://www.blackra1n.com. Click the Apple logo at the bottom of the screen (or Windows if you are on a pc).

Step Two
When prompted save the download to your desktop:

Step Three
Then double click the downloaded blackra1n zip file to extract the application, then double click the application icon to launch the program.

Step Four
Make sure your iPhone or iPod is connected to the computer then click the large make it ra1n button:

Step Five
Once your device reboots it will be jailbroken and you will notice a blackra1n icon on the Springboard. Make sure you have an internet connection and press to launch the application.
You iPhone will now be placed in recovery mode.

You will see a picture of GeoHot that replaces the regular recovery mode screen on your device

blackra1n will run and then your device will reboot.

A popup message will appear informing you that BlackRa1n is free software and if you appreciate it you can donate to GeoHot at geohot@gmail.com.

Step Six
Once your device reboots it will be jailbroken and you will notice a blackra1n icon on the Springboard. Make sure you have an internet connection and press to launch the application.

Step Six Once your device reboots it will be jailbroken and you will notice a blackra1n icon on the Springboard. Make sure you have an internet connection and press to launch the application.

Choose the installer application of your choice then press to select sn0w if you would like to unlock your device. Press the Install button at the top right of the screen to begin.

If you chose to unlock device using blacksn0w you will be presented with a Post Install log for sn0w. CommCenter will be restarted and there is no need to reboot. If your carrier doesn’t support 3G then disable it. Press the Close button to continue.

Step Seven
Once complete BlackRa1n will respring your iPhone and you will find the installer package of your choice on the Springboard.

Step Eight
Once you have confirmed your installer package is working correctly you may use the Uninstall blackra1n button inside the BlackRa1n app to remove it from your springboard.

***THANKS: A big thanks to Geohot for making this jailbreak and unlock possible. Also thanks to those who contributed to making it a success. You can donate to Geohot using the button below. Please note these donations go to Geohot and not to iClarified.