I have an iPod nano (5th generation). I want to know if it works with Ubuntu without problems? Ipod Nano 5Gen
It works, though the experience is a little different than with iTunes.
This site lists the applications that will allow you to copy music to and manager the music on your iPod.
Specifically, iPod up to 5g are supported through libgpod. iPod nano 6g is not supported and is reportedly difficult to support with anything other than iTunes.
If you don't have ubuntu yet, feel free to download and try it on a USB stick or on a LiveCD so you can see what it's like.