Notice : This is just Beta version, I still recommened Blackra1n be the first Choice to Jailreak your iPhone .

You should Know the differences between blackra1n and Redsn0w

*It uses our original Pwnage bootrom exploit for iPhone 2G, iPhone 3G, and iPod 1G. (Because it’s a bootrom exploit, it can’t be fixed by Apple without a new hardware release.) Note that redsn0w 0.9 does use the USB exploit for iPhone 3GS and iPod 2G running 3.1.2, but that exploit will be fixed in Apple’s next FW release.

*It offers custom logos and verbose boot

*It installs Cydia without needing a separate download
*It’s not as fast (but redsn0w handles more variations )

What’s different if I have a late-model device

If you have a late-model iPhone 3GS, or if you have an iPod touch 2G whose serial number begins with “MC”, then you are currently restricted to “tethered” rebooting. That means you need to connect your device to a computer to complete the boot after a reset. Also, these devices cannot have custom logos.

redsn0w will ask you whether or not you fit in this category when used with the iPhone 3GS or iPod touch 2G. If you have a late-model device and don’t give redsn0w the correct answer, you will likely need to do a system restore to recover from the mistake.

To do a tethered boot after your late-model device resets for some reason, either run redsn0w again and select “Just boot tethered right now”, or run blackra1n.
What if I’m already jailbroken?

If you’re already jailbroken, redsn0w can still be used to change your boot logos, revert back to the stock logos, or switch verbose booting on and off. By selecting “Already Pwned” you can bypass the steps normally needed to enter the jailbroken state.
Is it safe?

The Windows version has been tested by small groups of volunteers on IRC and our blog since mid-January. That being said, this is still a beta and if things go wrong you may have to do a system restore…so make sure your data is synced before trying the beta.
Beta feedback

Here is the Redsn0w guide

Redsn0w is an easy to use, multi-platform, multi-device jailbreaking and unlocking tool for the iPhone 2G 3G 3GS and also the iPod touch (first and second generation). Just like Blackra1n, Redsn0w jailbreak the 3.1.2 firmware already installed on your device, so before you proceed, you must have installed the original 3.1.2. Note that late-model iPhone 3GS and iPod touch 2G whose serial number begins with “MC” are currently restricted to “tethered” rebooting. That means you need to connect your device to a computer to complete the boot after a reset. Also, these devices cannot have custom logos.

Download Redsn0w 0.9

Windows Version
Mac Version

Step 1. If you have not already, download the original firmware 3.1.2 on the desktop of your computer. In case of unlocking an iPhone EDGE, to be sure you also download the two files Bootloader: bl39.bin and bl46.bin

Step 2. Connect the iPhone / iPod to PC or Mac

Step 3. Launch the application and click on Browse. Select the original firmware 3.1.2 from the desktop of your computer and then click on Next

Step 4. It will start an automatic process (and very fast) which will be downloaded and patched the kernel.

Following a new screen will appear. Cydia is already selected.

*Install Cydia: Main reason why we jailbreak iPhone.
*Verbose Boot: Will allow you to replace the boot with the apple (boot chart) with the verbose mode, or the ability to see everything that is loaded at startup;
*Custom Boot Logo: Bore with classic apple startup, change with your face or whatever else. Size should be 320X480.
*Recovery Custom Logo: A logo that will replace the classic Recovery;
*Already Pwned: Select if you want to install the verbose boot or change the boot and recovery logos on an iPhone on which has already been to jailbreak;

Step 5. Now you will be asked to put the iPhone in Recovery Mode (iPhone 3GS) or DFU (the other iPhone / iPod).

How to put your iPhone in recovery mode :

1.Turn the device completely off and disconnect it from cable/dock.
2.Hold down the home button.
3.While holding down the home button connect to a computer with a cable (easiest) or dock.
4.Keep holding down the home button until you see a connect-to-iTunes screen You are now in recovery mode.
5.To escape Recovery Mode and power the phone off simply hold down power and home buttons for ten seconds.

How to put your iPhone in DFU mode :
1.Connect your iPhone to your computer.
2.Turn iPhone off.
3.Hold power and home together for 10 seconds (exactly).
4.Release power but keep holding home until the computers beeps (observed on a PC) as a USB device is recognized.
5.A few seconds later iTunes should detect your iPhone.
6.If the Restore Logo is present on the screen, you are in Recovery Mode, not DFU.

Step 6. Once you are in recovery mode/dfu mode redsn0w will start another automated process to complete the Jailbreak.