Note: Jailbreakers and unlockers should stay away from iOS 4.1 as there is NO jailbreak for iOS 4.1 at the moment. Also, the baseband gets updated which will nullify your carrier unlock.
Download iOS 4.1 [Direct DOwnload]
Download iOS 4.1 for iPhone 4 Download iOS 4.1 for iPhone 3GS Download iOS 4.1 for iPhone 3G Download iOS 4.1 for iPod Touch 4G Download iOS 4.1 for iPod Touch 3G Download iOS 4.1 for iPod Touch 2G
Once you download the ipsw file, you can install it manually by going to iTunes, then hold “Shift” key and click on “update” button. Locate and select iOS 4.1 IPSW file. Now let the iOS 4.1 install complete.