I believe that itunes uses the AAC format . If Itunes sells you the song then you are able to copy it 3 times. If you get a new computer you need to de register your old computer w apple so as not to waste one of your 3 copys. I have heard some say if you burn your itunes bought song onto a disc and then copy that burned copy you bypass this issue. If you are simply ripping your own cd to your own computer you own the rights (I think) and you can make as many copies as you want. I have ripped about 400 cds using itunes AAC at 160 bit rate to generally pretty great results...