A new 80 GB iPod is most likely a "Classic" and will not work with Rockbox.
The rest of your question appears to be general iTunes information we don't have.
Mind you, Rockbox is not a modification of the Apple software, it is a wholly separate program, and despite its ability to play music placed on your iPod by iTunes, has nothing to do with iTunes.
PS - I edited your post to remove the silly font call.