Forgive my limited iPod knowledge even though I started out with the original but....

What about the music I already have bought on iTunes? Will it now play on any devise? Or, is this just for newly purchased music?

BTW Rich, which model Nano do you have? Is it the last version (square'ish) model? I have a 60GB vidio iPod and my wife has the square Nano. I hate that Apple went back to the longer rectangular Nano.