This is by far the easiest way to jailbreak your iPhone or iPod Touch. And yes, this works with all device models out as of the date of this post.

Applying a jailbreak is safe and will not and can not permanently ruin a device. Even if you screw it up halfway through and brick the unit, there’s a way to undo it: How to fix a “bricked” iPhone/iPod Touch

1.) Backup your entire device in iTunes.

Applying this jailbreak won’t delete any of your stuff, but in the event something goes awry, or you brick the unit, it’s good to have a snapshot of the device exactly the way it was before you started. Just right click the device on the menu listing on the left and select “Back Up”. This doesn’t take too long, and will save everything on the device – texts, pictures, contacts, apps, everything – minus the music.

2.) Download the 3.0 Firmware.

Even if OS 3.0 is already on your device, you still need to download the ipsw file since the jailbreak utility needs to patch it.

• iPhone 2G Users – iPhone1,1_3.0_7A341_Restore.ipsw
• iPhone 3G Users – iPhone1,2_3.0_7A341_Restore.ipsw
• iPhone 3GS Users – iPhone2,1_3.0_7A341_Restore.ipsw

As for you iPod Touch users, Apple hates you and wants to charge you $10 for the OS 3.0 upgrade while the iPhone users get a free ride, which is complete bullshit. Minus the phone, it’s the same thing and just as expensive, so there’s absolutely no reason why you shouldn’t get it for free as well. Luckily, doing a Google search on the files needed brings back a ton of places to download it from.

• iPod Touch 1G Users – iPod1,1_3.0_7A341_Restore.ipsw -  (or download from Megaupload)
• iPod Touch 2G Users – iPod2,1_3.0_7A341_Restore.ipsw – (or download from Megaupload)

3.) Download redsn0w 0.8 below based on the OS you use, extract the files, and run the .exe inside.

• Windows
• Mac
• Linux

4.) Browse and select the ipsw that you downloaded in Step 2.

Once you do, redsn0w will display “Processing Firmware” and then “IPSW successfully identified.” Click next, and redsn0w will begin patching the IPSW file.

5.) Select “Cydia” on the following screen once the patching process is completed. You could add Icy as well, but for the sake of simplicity, I’ll just stick with Cydia. They are both package management systems that allow you to install various utilities and system tools, such as Open SSH, onto the device. Click next.

6.) Put the device into recovery mode.

On the final screen, redsn0w actually gives you detailed steps on how to do exactly that, but I’ll go over it anyway

• Unplug any cables connected to the device
• Hold the SLEEP/WAKE button at the top until “Slide to Power Off” appears – then slide it to do just that. It might take 10 – 20 seconds to power down.
• Wait at least 5 seconds after the device is completely off.
• Press and hold the HOME button, and at the same time, plug the USB cable back into the device. Once you see the following image, it’s okay to release the home button.

7.) You’re done!

At this point, redsn0w should have automatically detected the device in recovery mode and started the automated process of uploading the new stuff. It might take an additional minute or two and a couple loading screens, but you should be back at your home screen once the process is completed and the Cydia icon (and/or Icy if you chose it) should be hanging out there somewhere.