Considering updating your iPhone forces you to update to the latest software available for the device, updating an iPhone 3GS now will update it to iOS 6.
You cannot. If you buy a new iPod or iPad or iPhone, it comes in iOS 4.3.3 and you have a choice to update to IOS 5 or not.
You need to connect to to the computer that is authorised for your iPhone and update via iTunes.
The current latest iOS version on the iPhone 4S is iOS 6.1.3 considering iOS 6.1.4 is for the iPhone 5 only. iOS 7 will be available for the iPhone 4S this fall.
iOS 6 came out of beta September 21, 2012 with the launch of the iPhone 5. You can update to the latest iOS 6.1.3 (6.1.4 with the iPhone 5) by going into Settings>General>Software Update or plugging your device into an iTunes authorized computer if you are running anything older than iOS 5. If you are not fond of the iOS 7 update, then you must update to iOS 6 before this fall because after that, Apple forces you to only update to the latest software version or not at all. But you don't have to worry about this is you have a 4th gen iPod Touch or iPhone 3GS which can't get iOS 7.
iOS 6 is the software that was launched with the iPhone 5. You can run this software version on an iPod Touch (4th or 5th gen), any iPad except the original, and the iPhone 3GS, 4, 4S, and 5. You have only this summer to update to it if your device is eligible for an update to iOS 7 coming this fall. If you are running iOS 5, you can update to it from Settings>General>Software Update. If you are running any older iOS, you must plug your device into an iTunes-authorized computer to update. The update is entirely free by the way. You can see more about what features it brings on Apple's website.
Yes, just dont choose to update to iOS6
If you are running iOS 5, you can update to iOS 6.1.3 (or 6.1.4 on iPhone 5) by going into Setting>General>Software Update. If you are running iOS 3 or 4, you can update to the latest software by plugging your iDevice into your iTunes-authorized computer and wait for your device to be recognized. Once this is done, there should be a pop-up to download and update to the new iOS. Everything should be self explanatory by then.
You cannot. The iOS 5 update is only for Iphone 4, iPod touch 4, iPad 1, iPad 2
Keep in mind, the 1st generation iPod Touch and original iPhone cannot update to iOS 4. For all other devices, the update is free. Just know that because you are forced to update to the latest version of iOS, the only devices you can still update to iOS 4 are the iPhone 3G and iPod Touch 2nd generation. All other devices will update to either iOS 5 or 6 using this same method. You plug your device into your iTunes-authorized computer and wait for the pop-up that there is a new software version to update to. You click download and update (or whatever it says) and agree to terms and conditions. Then you must wait until the download an installation is complete before unplugging your device.
The apple iOS 5 update IS OUT NOW
The apple iOS 5 update IS OUT NOW