iPhone Dev Team has just updated redsn0w to 0.9.5 beta to jailbreak iphone OS 4.0, however this tool works on iphone 3g only with 4.0 beta firmware. This new beta version of redsn0w is been released now only for Mac but windows version will be coming soon.

Note: Both the iphone 4.0 beta firmware and Redsn0w 0.9.5 beta are not meant for normal users as they might not able to unlock their phone after upgrading to iphone 4.0 beta firmware, so better stay away from both of these and wait for the iphone 4.0 firmware final release.

iPhone 4.0 Jailbreak Important Things To Be Kept In Mind

• Redsn0w 0.9.5 BETA supports only iPhone 3G (atleast for now) and requires Mac OS X.
• You should be a registered Apple developer or your iPhone UDID should be registered with any iPhone Dev, so you can install the beta version.
• If you update to OS 4.0 beta your Baseband will be at 05.13 and you may not be able to unlock to use until the next release of ultrasn0w and blacksn0w.
• Redsn0w 0.9.5 uses the same pwnage2 DFU-mode exploit that the Dev-Team has been using since the 2.x days.
• The current Beta of Redsn0w 0.9.5 is not for normal users so if you are not a developer stay away

Jailbreak Guide For iPhone 4.0 Beta OS

1. Download iPhone OS 4 Beta for iPhone 3G. [ You need to be a developer for this ]

2. Update your iPhone 3G to  latest firmware with a file named iPhone1,2_4.0_8A230m_Restore.ipsw [ Pressing Shift+Restore in iTunes ]

3. Download redsn0w 0.9.5 or from here and then run and point it to the original iPhone OS 4 Beta firmware you download for iPhone 3G

4. Check to “Install Cydia” and click “Next”.

5. Now, iphone is should be both turned OFF and then connected via USB Cable to the computer before you click “Next”.

6. Put your iPhone in recovery mode by pressing the Power / Sleep and Home buttons same time.

7. Once your iphone automatically reboot once it is jailbroken

Disclaimer – This guide for testing and educational purpose only, So we are NOT going to be responsible for any damage caused to your device after following this guide. 

Apple has finally revealed the features and functions in iphone OS 4.0, it seems to be the most revolutionary os with some great features which will change the way iPhone used to work before.

Following are the list features confirmed by apple at apple iPhone OS Event going on right now as I m writing this post

iPhone OS 4 New Features

• iPhone OS4 has 1500 new APIs for app developers, means thousands of new possibilities
• iPhone OS4 has a 5x digital zoom in Camera Softwaew
• iPhone OS4 has a playlist create feature
• Smart Multi-tasking support without draining battery, which is biggest road-block in multi-tasking
• iPhone OS4 has tap to focus functionality on video capture
• iPhone OS4 allows to geo-tag photographs through default camera application
• it has a Spell Check feature
• it can synchronize IMAP notes with email accounts
• it officially supports bluetooth keyboards
• Web search suggestion
• the iPhone home screen can have a wallpaper without need to jailbreak
• Search within SMS and MMS
• It Supports Nests playlists (create playlists inside playlists)
• Photograph rotate functionality in built in the photo viewer app

iPhone OS 4 Multi Tasking Features

• Double click home button, window raises, shows apps that are running in background.
• Click the apps you want to swithc to and it opens that app by sending the current app to background

Note: Apple added multitasking while preserving battery life and performance by observing tens of thousands of apps in the app store and selecting the services the apps need to run in background. Apple has implemented those services, and providing those services as APIs to developers so they can add multitasking while preserving battery life

More iPhone OS 4.0 Navigation Based Features

• Better and improved GPS
• Recieve calls and use Navigation at the same time, as call runs in background now
• Turning navigation / location services on and off is easier with new UI.
• Turn on location services as per applications, no need to turn on and off for all, it saves battery.
• Location services indicator in top status bar besides battery indicator.

Folders In iPhone OS 4.0

• Add Folders on iPhone to organize apps better:
• Drag and drop apps onto one another to create folders
• The name of the folder is automatically created and you can edit it later
• Now you can organized all your apps in folders as you like them, you can organize all games in one folder, or the most frequently used in one etc etc.
• Group up to 9 Apps in one folder
• Flick can upload photos in background, while you can continue viewing photos

New Email Features In iPhone OS 4.0

• Official support for more than one exchange account
• Email App with fast inbox switching to switch between email accounts
• Organize email as discussion threads rather than individual mails

iBooks Announced for iPhone / iPod Touch

• Buy your books once and read them anywhere. We’re wirelessly syncing pages and bookmarks automatically.
• A free book- “Winnie the Pooh” for customers to get a feel of it.

Gaming Support on iPhone OS 4.0

• 50700 Games available for iPhone, mush more than any other dedicated gaming console
• New social gaming network added for iPhone / iPad
• New gaming network does automatic matchmaking, finds others with a similar ability and match them against you

Mobile Advertising Platform, iAds

• A way to make some money from free iPhone Apps
• Free App developers can put ads provided by iAds on their Apps
• Expected impressions from iAds – 1 Billion ad impression per day
• iAds to focus on emotions and interactivity
• iAds is inbuilt in iPhone OS
• Apple will sell and host ads on its servers
• Good News For Developers  60% of revenues generated will go to the App developers

Devices which support iPhone OS4 and its features

• For iPhone 3G and iPod touch 2nd gen, they will run many things, but not everything — they will not support multitasking, the hardware just can’t do it.” as explianed by Steve
• iPhone OS 4 to the iPad this fall