Drag n Drop Songs to an Ipod

I am figuring if I wan to get an iPod and I need to confirm this once and for all with people who own iPods.

When you wan to transfer songs to your iPod to listen to, can you just plug the iPod to your PC, and drag-drop mp3s into it?

Or do u HAVE to use iTunes to tranfer the music?

Does the iPod Linux project removes this requirement?