Upgrading Samsung Devices by Samsung Kies

This is the official upgrading operating system for Samsung mobile phones
To upgrade your Samsung device you will need
Charged Samsung device (more than 60%), original USB cable and installed Samsung Kies software (Link below)

Connect your device to computer by USB cable (Wait untill some files will be downloaded)
1- Open Kies then you will see a message announce you that there is a "New firmware is available"

2- Click on Upgrade firmware then aceppt and start

(it will download some files to prepare upgrading -10MB approx- ) 
Then Kies will start downloading the firmware (1GB approx), extract firmware and install it

YT Video link : http://www.youtube.com/watch?v=H2OACWSy0Oc

Notes :
~ Never disconnect the USB cable while upgrading
~ Its better to put your device in flight mode

Downloads :
Latest Samsung Kies Here