This has been a very common question ever since the release of the Zune media player. Helping your audience understand how they can enjoy a connected, end-to-end experience from creation to delivery of digital media is a great catalyst in spurring creative energies and excitement about investing in tools of creative expression.
Click on the link below to learn more about how to provide an optimal experience for Zune, including file format compatibilities, file conversion, and encoding information.
http://www.zune.net/en-us/support/howto/start/providecontent.htm#section3