the contents of your iTunes library onto the DVD. You probably cannot do it from within iTunes but if you export the library out as AAC, AIFF or MP3 then once it is burned onto the DVD is should be playable.
The other alternative is to go to the local Mac store and ask them how to do it.
I would like to know how to backup all of my ipod's music to a DVD cd? because the Mac Store can do it here where i live, but, they charge $75 dollars. I would like to know, if someone knows how to do this please tell me