Apple has released iOS 4 update for the iPhone and iPod touch yesterday. iOS 4 is available for iPhone 3GS, iPhone 3G and 2nd & 3rd generation iPod touch.
The update include many features including multi-tasking, organizing apps in folders, unified inbox and more. You can learn more about iOS 4 from this walkthrough at TiPb which we translated to Arabic here.
To install the update run iTunes 9.2, connect your iPhone or iPod touch then go to the device summary page and click Check for Update to begin.
If you have jailbroken your device then make sure it is compatible with iOS 4 first.
Arabic version of this post on SaudiMac Arabic Edition.