It is hard! It requires modifying system files... but if you have the know how and the guts you can get your iPod to work with iTunes under Linux!
I have written up my full instruction in the Tips & Tricks section. I cannot guarantee they are well written or easy to follow, i am a developer not a technical writer. If you have questions ask.
Again if the idea of being root and modifying system files fills you with doubt, then stop here and wait for us to work to clean this process up and make is easy for you. We hope to have it be much easier maybe a 3.1.1 or point release soon after 3.1
-aric