You can't burn standard audio files to a DVD with Nero or any other burner software. The only solution is to burn them on your DVD as MP3s or WMA if your player supports them. For the car, you are stuck with CDs unless you have one of those exspensive DVD 7" video players (but some support MP3s). There are two official DVD audio formats that exist at the moment; DVD-audio and SACD, both of which cannot at this time be burned onto a medium by end-users. And you will need to buy a DVD player and the disks that support either format.
http://www.disctronics.co.uk/technol...daud_intro.htm