its in the manual but its not on the car unless you ordered it. bought mine yesterday and had inquired the dealer about it and he knew about it too. we both agreed its a dumb move by mazda to not just include it with all cars now, but he says its like $390-$450 just to swap the headunits to the MP3 compatible one.
to me, i have a basically brand new ipod at home here (30GB) that i hardly ever use except at the gym sometimes, i'm gonna just start learning to deal with the evil that is itunes and start using that, rather than spend money to swap head units when i have a perfectly good ipod collecting dust i would go aftermarket but i bought this car to get a somewhat complete package that would deter me from "modding" things and dumping money in it, plus i want to keep the functionality of the info bar and my steering controls.