How to Jailbreak Your iPhone 3GS, iPhone 4, iPad, iPod Touch Using RedSn0w (Windows and Mac) [4.3.3]
These are instructions on how to jailbreak your iPhone 3GS on the 4.3.3 firmware using RedSn0w for Windows. The Mac version of this tutorial is absolutely the same
Make sure not to update to iOS 4.3.3 if you need an unlock as one is not yet available unless you opt to use the iPad baseband.
IMPORTANT FOR UNLOCKERS
During this process you can update your baseband to the 06.15 version. If you are on 05.14 or 05.15 or higher you will need to do this to unlock. You do not need to do this for jailbreak only. Please read the following very carefully before deciding whether to do this.
1. There is no way to come back down from 06.15, and there’s no hiding the baseband version from Apple. You’ll be voiding your warranty in a very obvious way.
2. If some future baseband comes out with a critical fix, you won’t be able to update to it if it remains down in the 05.xx sequence (then again, you wouldn’t update to it if you wanted to keep your unlock anyway).
3. Starting with FW 4.2.1 if you have 06.15 on your iPhone you won’t ever be able to restore to stock firmware (it will fail). You’ll need to only restore to custom IPSWs (then again, if you’re unlocker you should already be doing that).
4. There are reports that 06.15 may disable your GPS. The iPhone Dev-Team is currently working on a fix.
Don’t update to 06.15 if you don’t need to! Only do this if you need the unlock and you’re stuck on 05.14 or 05.15, and you’re willing to assume the above risks. If your baseband is already unlockable and you are on a lower firmware version then use PwnageTool to update to 4.3.3 without upgrading your baseband.
Create a folder on your desktop called Pwnage
Download RedSn0w for WINDOWS from here and place it in the Pwnage folder.
Download RedSn0w for MAC from here and place it in the Pwnage folder.
Likewise, download the latest 4.3.3 firmware from below and place it in the same folder. 4.3.3 (3GS), iPhone 4 and / or iPad or iPod Touch:
4.3.3 (iPhone 3GS): iPhone2,1_4.3.3_8J2_Restore.ipsw
4.3.3 (iPhone 4): iPhone3,1_4.3.3_8J2_Restore.ipsw
4.3.3 (iPad 1): iPad1,1_4.3.3_8J3_Restore.ipsw
4.3.3 (iPod Touch 4G): iPod4,1_4.3.3_8J2_Restore.ipsw
4.3.3 (iPod Touch 3G): iPod3,1_4.3.3_8J2_Restore.ipsw
Once iTunes has finished updating your iPhone to the desired firmware open the Pwnage folder on your desktop and launch the redsn0w application from the redsn0w folder we extracted earlier.
Verbose boot displays detailed information on boot of your device and is generally only needed by developers and advanced users.
Make sure Cydia is selected. For this tutorial we will also select Custom boot logo and Custom recovery logo.
Once this is complete you will be notified that RedSn0w is done. Click the Finish button. When your iPhone finishes rebooting (5 minutes or so) it will be jailbroken with Cydia on the SpringBoard.
*As usual a big thanks to the iPhone Dev-Teams, Geohot, and I0n1c for their hard work and contribution to the iPhone community.
**Windows 7 users can try running RedSn0w as an administrator in Windows Vista or XP compatibility mode if you experience any difficulties.
Source is iClarified