The latest software update for the iPhone and iPod touch devices have been released by Apple and is now available for download via iTunes and we also included direct links incase you want to do the update manually!
Direct Download Links to iOS 4 Firmware
Note : We are experience pretty slow speeds for the above links as too many users are trying to download the update. We guess speeds should improve soon !
You require iTunes 9.2 in order to perform this update. iTunes 9.2 was initially available only for Mac but now its available for windows also. Do backup you iPod or iPhone before performing this update and make sure you transfer all the apps to the Desktop.
via TUAW