Q: ios, ios

Only the iPod with cameras can go to iOS 6.

A 1G iPod can go to iOS 2.2 via iTunes and iOS 3.1.3 via

Purchasing iOS 3.1 Software Update for iPod touch (1st generation)       

https://buy.itunes.apple.com/WebObjects/MZFinance.woa/wa/touchLegacyLandingPage

A 2G to 4.2.1. Requires iTunes version 10.X. If a Mac it requires OSX 10.5.8 or later.

A 3G to 5.1.1  Requires iTunes version 10.5 or later

iOS: How to update your iPhone, iPad, or iPod touch

Identifying iPod models