Apple has released the iPhone 3.1 OS for iPhone 2G / 3G / 3GS. The new version of iPhone OS is now available for free download and you can upgrade your iPhone via iTunes. You do not need to upgrade to iTunes 9 to download the update. The upgrade of iPhone OS should also work on iTunes v8.2.

Below is Apple’s list of new features for iPhone OS 3.1 :
  • Genius recommendations for Applications – similar to the genius feature for songs. Base on your existing iPhone applications you have downloaded or purchased, iTunes look for other applications and recommend those that you may interest.
  • iTunes 9 Support -Align with the release of iTunes 9, iPhone 3.1 supports genius mixes, improved syncing option for music, movies, TV shows, etc. It also supports the app reorganization directly in iTunes.
  • Use iTunes on your computer to drag apps onto virtual Home screens, then sync them to your iPhone.
  • Redeem iTunes gift card, code and certificates in the App Store
  • Display available iTunes account credit in the App Store and iTunes Store
  • Browse and download ringtones wirelessly from iTunes Store
  • Save video from mail and MMS into camera roll
  • Option to “Save as new clip” when trimming a video in iPhone 3GS
  • Better iPhone 3G Wi-Fi performance when Bluetooth is turned on
  • Remotely lock iPhone with a passcode via MobileMe
  • Use Voice Control on iPhone 3GS with Bluetooth headsets
  • Paste phone numbers into the keypad
  • Option to use Home button to turn on Accessibility features on iPhone 3GS
  • Warn when visiting fraudulent websites in Safari
  • Improved Exchange calendar syncing and invitation handling
  • Fixes issue that caused some app icons to display incorrectly
Let me remind you, if you’re relying on ultrasn0w for unlocking your iPhone, please stay away from iPhone 3.1. Your iPhone will be locked again after the upgrade and presently, ultrasn0w cannot unlock iPhone with 3.1 OS.Needless to say that there is no jailbreak yet for iPhone 3.1. I will keep you updated and write tutorials on how to jailbreak iPhone 3.1 as it becomes available.