We have already carried out a comprehensive detail by detail guide how to jailbreak iOS 4.1 in apple iphone 4 and apple iphone 3GS model. All you have to do is to improve your own ipod 3g or ipod 4g to the newest iOS 4.1 firmware, then stick to the detail by detail guide posted in this article to be able to Jailbreak the mentioned products in iOS 4.1 using Limera1n.