There are to ways to update your iPod Touch:
- If your iPod Touch is currently running iOS 5, you can update it on the device itself. Go into the settings on your iPod and tap on General. Then tap on software update; from then on it's pretty self explanatory.
- Plug your iPod Touch into your computer. Click on iTunes and then click on your iPods name. After you've done that, click on software update.
iOS 6 only supports the iPod Touch 4th & 5th Generation.
Connect the iPod to your computer and update via iTunes
A 1G iPod can go to iOS 2.2 via iTunes and iOS 3.1.3 via
A 2G to 4.2.1. Requires iTunes version 10.X. That requires a Mac with OSX 10.5.8 or later. With 1OSX 10.4.11 you can only go to iTunes 9.X which gets you as high as iOS 4.1
A 3G to 5.1.1 Requires iTunes version 10.5 or later
A 4G to 6 Requires iTunes version 10.7 or later. That requires a Mac with OSX 10.6.8 or later