Currently Being ModeratedMay 23, 2013 9:19 PM (in response to psturn)
If it's a second generation model, no.
Apple did not update the 8GB's hardware when it released the third generation models.
If it's a fourth generation model, update it from iTunes on a computer.
Currently Being ModeratedMay 23, 2013 9:20 PM (in response to psturn)
Depends on the version of iPod it is. Your iPod may only be elgible to update to 4.2.1. To my knowledge the 2nd gen iPod touch has a limit of 4.2.1 and the 3rd gen iPod touch has a limit of 5.1.1. See iOS 4: Updating your device to iOS 5 or later
Currently Being ModeratedMay 24, 2013 8:42 AM (in response to uselessSABOTAGE)
If it is an iPod Touch 2G, it can't be done. Due to your device's internal CPU and RAM, it will always be limited to running apps that use iOS 4.2.1 or earlier. Be sure to keep backups of any vintage apps you use. Once a developer updates their app past your maximum iOS, a compatible version can never be downloaded again.
If it is an iPod Touch 3G or greater, then iTunes should be able to update it.