Basically, you can't. Once an OS update has been installed, you can't go back.
The apple iOS 5 update IS OUT NOW
The apple iOS 5 update IS OUT NOW
You do not get iOS 4.0.2 when you update an iPod to iOS 4.1. iOS 4.0.2 is an earlier version and precedes iOS 4.1. The next version after iOS 4.1 will be iOS 4.2.
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 can update it to iOS 5 the same way you update it to any other iOS version. The 4th generation (and indeed the 3rd generation) iPod Touch can be updated to iOS 5.
iOS 6.0 is expected in October of 2012.
The iOS 4.3.5 update was a security fix.
The 8gb iPod is not capable of downloading the IOS 4.3 update. If you want to run IOS 4.3 on your iPod, you will need to update to at least a 32gb iPod.
If you update your iPhone/iPod, you will remove the jailbreak, then you would have to wait until the jailbreaking websites invent a jailbreak for the new ios, but why update if you jailbroke it?
Dont update to iOS 6. It runs bad on the ipod touch and when you jailbreak it, it will be only slower. I will downgrade to iOS 5.1.1 since it is the best for me right now.
go into its tab in itunes and click update
If you have an iPod Touch 3rd generation, you can easily update to iOS 5.1.1 by plugging in your device to your iTunes-authorized computer and waiting for the pop up to download and update to the new software. If you are already running an earlier version of iOS 5, you can update wirelessly by going into Settings>General>Software Update. If you have a 4th generation iPod Touch, then you must update to iOS 6 because you are always forced to update to the latest iOS version available. I you have a 5th generation, you cannot downgrade to iOS 5.1 because that is not legally allowed by Apple and requires hacks.