How do I update iOS on my 3rd generation iPod . There is no update button under settings

The option to update without the computer (Over the air) was made available with iOS 5. If your iDevice is using a version of iOS lower than 5, you will need to use iTunes on your syncing computer to perform the upgrade. Use the Apple link below as a guide for the upgrade.

http://support.apple.com/kb/HT4972

Also read the instructions from the section entitled "Update your device using iTunes" at the link below.

http://support.apple.com/kb/HT4623

Information regarding transferring purchases from your iDevice to iTunes on your syncing computer can be found at the link below.

http://support.apple.com/kb/ht1848

OTA (over the air) Updates weren't added until iOS 5. You probably have an earlier version. You can update through iTunes:

http://support.apple.com/kb/ht4623

Note that the 3rd generation iPod touch is not supported with iOS 6.0 or later. But yes: if you have a version of iOS 4 or earlier you can udate your 32GB or 64GB iPod touch through iTunes.

Some users who think that have a 3G iPod really have a 2G. A 2G can only go to iOS 4.2.1 (requires iTunes 10 or later on the computer), a 3G to 5.1.1 (requires iTunes 10.7 or later on the computer).

Identifying iPod models

iPod touch (3rd generation)

iPod touch (3rd generation) features a 3.5-inch (diagonal) widescreen multi-touch display and 32 GB or 64 GB flash drive. You can browse the web with Safari and watch YouTube videos with Wi-Fi. You can also search, preview, and buy songs from the iTunes Wi-Fi Music Store on iPod touch.

The iPod touch (3rd generation) can be distinguished from iPod touch (2nd generation) by looking at the back of the device. In the text below the engraving, look for the model number. iPod touch (2nd generation) is model A1288, and iPod touch (3rd generation) is model A1318.