Apple has made the decision to keep its DRM system proprietary. Songs you've purchased on iTunes play on an iPod and only an iPod. Unless Audi has licensed the FairPlay DRM from Apple (highly unlikely since *nobody* had licensed it so far), then the answer is no.

Of course, you could always burn a regular music CD from these files and then re-rip them as MP3. But then that would be in violation of the Digital Millenium Copyright Act and is a federal crime. If that bothers you, write your representatives or start donating to the Electronic Frontier Foundation www.eff.org.

Thanks.<ul><li><a href="http://home.comcast.net/~jrdailey/Holiday2004/A4_Ridge.jpg">My A4 2.8QSTip</a></li></ul>

AAC is a codec. Fairplay is a Digital Rights Management (DRM) system. AAC is not necessarily tied into Fairplay. You can rip music from your own CDs in AAC format and play it on basically any device that supports AAC. Only music purchased from Apple's iTunes utilize Fairplay, which as you correctly point out is unlikely to work on Audi's NAV system.

Regardless, none of this actually answers A3NDY's question.

That's the beauty of MP3, it's a universal standard that you can play anywhere on any device. That's part of why the RIAA is so opposed to it.
MP3 may not be as efficient as AAC in terms of sound quality per megabyte, but it more than makes up for these shortcomings by its ubiquity and compatibility.