The Dev-Team has already upgraded its Redsn0w 0.9.8b5 to jailbreak iOS 5 beta 5.
As for the previous iOS 5, the jailbreak is possible but it’s tethered, meaning that you have to plugin your iOS device to the computer and boot it in
tethered mode using Redn0w


.


Please note that you’ll not be able to unlock your iPhone using this method. An unlock for iOS 5 is still not possible.


This jailbreak does not work for iPad 2. If you have an iPad 2 jailbroken with JailbreakMe 3.0, stick to it because an untethered jailbreak for iPad 2 will not be available for a while.
This jailbreak will work on iPhone 3GS, iPhone 4, iPod touch (third and fourth generation) and iPad 1.




Download Redsn0w 0.9.8b5 for Mac
Download Redsn0w 0.9.8b5 for Win

This new “Custom IPSW” feature works for iPhone 4 and iPhone 3GS for now but it will be expanded later on. Redsn0w 0.9.9 b5 is currently available for Mac OS only but a Windows version will be released very soon.
Release Notes of Redsn0w 0.9.9b5:

With today’s official iOS5 release, redsn0w has been updated to 0.9.9b5 to include the public URLs for the IPSW files. This way, first-time iOS5 jailbreakers don’t need to supply the IPSW file manually. It’s still a tethered jailbreak on all except the old-bootrom iPhone3GS, and it doesn’t apply to iPad2 or the upcoming iPhone4S.



Because the jailbreak is currently only tethered for most devices, we’re not going to release a new PwnageTool yet. Instead, we’ve decided to build some of PwnageTool’s functionality into redsn0w (since you need redsn0w to “Just boot tethered” on every power cycle anyway). The new “Custom IPSW” button on the Extras screen will create a custom IPSW without the baseband update for 4.3.3 or 5.0gm (iPhone3GS and iPhone4 only, for now). Remember to NOT accidentally restore to the stock IPSW after you create the custom one! The custom one begins with NO_BB_ (for “no baseband”). On Mac iTunes, you select an IPSW by holding down the Option key while clicking “Restore”.



You must enter “Pwned DFU” mode before trying to use the NO_BB_ IPSW with iTunes (and your hosts file cannot be pointing to Cydia’s servers due to the new blob nonce mechanism they’re using in iOS5).



Version 0.9.9b5 is available only for Mac for now, until we can do more testing on the Windows version of “Custom IPSW”.
We’re currently working on a normal compatibility update for existing ultrasn0w unlockers. After that we’ll try to fix the iBooks issue on jailbroken iOS5.

Remember: If you rely on unlock DO NOT jailbreak directly using redsn0w, you need to create a custom IPSW and restore it manually in order to preserve baseband. On windows you can use Sn0wbreeze 2.8b8 to create (pre-jailbroken) IPSW file with baseband preserved.
How To Jailbreak With Redsn0w 0.9.9b5:


Step 1: Connect your iPhone to the computer and launch iTunes.
Step 2: Select your iPhone from the list of devices on the left. Now hold down Option and click the Restore button. Restore is preferred as it won’t create any wasted space on your iPhone.
(You can skip this step if iOS 5 is already installed on your device)

Step 3: Download (link) and Launch the redsn0w 0.9.9b5 for Mac OS

Step 4: Once RedSn0w opens click the Jailbreak button
Step 5: Plug your iPhone into the computer and make sure its OFF then click the Next button. RedSn0w will now guide you through the steps to get into DFU mode.

• Hold down both the Home button and the Power button for 10 seconds.

• Release the Power button and continue holding the Home button until RedSn0w detects the device.

Your iPhone will now reboot

Step 6: RedSn0w will now prepare the jailbreak data

Step 7: Select Cydia from the list of options and click Next.
Your iPhone will now be rebooted again and RedSn0w will begin uploading the new RAM Disk and Kernel.


Step 8: Once this is complete you will be notified that RedSn0w is done. When your iPhone finishes rebooting (5 minutes or so) it will be jailbroken and running iOS 5 final version.

Booting In Tethered Mode:
Once you have jailbroken you will need to rerun redsn0w to boot tethered.
Step 1: From the main RedSn0w menu click the Extras button.

Step 2: Select Just boot from the Extras menu to just boot tethered.

And that was it, happy jailbreaking! If you face any problem during this process feel free to ask for any kind of help.

EXAMPLE

Step 1: Download iOS 5 Beta 5 for your iDevice.

Step 2: Download iTunes 10.5 beta 5 for Windows and Mac. You need the latest pre-release beta of iTunes so that it sync with iOS 5 beta 5.

Step 3: Install iOS 5 beta 5 on your device using your computer. Don t actually set up your device on iOS 5 beta as first you need to jailbreak it. Follow this tutorial to jailbreak iOS 5 beta 5 tethered and after that, boot your device tethered.. Keep in mind that this does not work with the iPad 2.

Step 4: Basically, you need to delete a key and string from within the filesystem of your device in order to install iOS 5 beta 5 without developers account. To gain access to the filesystem, you need software. i-Funbox for Windows and iPhone Explorer for Mac are the two most perfect software for this job.

Step 5: Launch the relevant software and go to this path: filesystem/library/coreservices/systemversion.plist. Once you locate the systemversion.plist file, right click on it and then open it in notepad. Once opened, locate and remove: <key>ReleaseType</key> <string>beta</string>. When you remove it, save changes to the file.

Step 6: Once you have done this process, reboot your device. Because it is jailbroken, you will have to boot it tethered. Your device is now running iOS 5 beta 5 without developers account or a UDID activation. No more this device is not registered as part of the iphone developer program errors. If you did this on an iPhone, you shall be able to use cellular services as well.

Note: If you are a unlocked iPhone users, please stay away from the iOS 5 beta 5 in case of losing your unlock. Hope it is helpful. Here we also provide the iOS 5 beta 5 download in the following. If you want to know more, please stay tuned, we will post better information.