These are step by step instructions on how to use QuickPwn 1.1 for Apple Mac OSX to jailbreak your 2.1 iPhone or iPhone 3G.
Create a folder on your desktop called Pwnage
Download QuickPwn 1.1 from here and place it in the Pwnage folder. Likewise, download the latest 2.1 firmware from below and place it in the same folder.
Now double click to mount the QuickPwn [QuickPwn_1.1.dmg] archive that you downloaded above. Then drag the QuickPwn application into the Pwnage folder you created on your desktop.
Now double click the icon to launch QuickPwn from your Pwnage folder.
Click OK to accept the copyright notice.
Connect your iPhone or iPhone 3G into the computer when asked, then click OK.
QuickPwn will now automatically detect the device that you connected!
QuickPwn will now attempt to find the latest firmware for this device
You will be asked if you would like to replace the original boot and recovery logos on your iPhone. Select Yes or No to continue.
QuickPwn will now build your custom IPSW.
You will be prompted to enter your username and password. After doing this, then click OK.
QuickPwn will now guide you on how to put your iPhone into DFU mode. Pay attention and do exactly as QuickPwn directs you. First, turn off the device.
Next, you will be prompted to hold both the Home and Power buttons for 10 seconds.
Finally, you will let go of the power button and continue holding down the Home button for another 10 seconds.
QuickPwn will now begin sending information to your iPhone.
You will notified that QuickPwn is modifying your iPhone. The process will take some time and will cause the iPhone to reboot. Do not do anything until the process has completed.
After your iPhone has rebooted it will be jailbroken and have both Cydia and Installer on the Springboard. Congratulations!