(I realize this is not in fact new, sorry about the outdated post, but if your still interested, read on)

Microsoft has released it's own zune theme for your desktop, and it looks great! You can easily download it here, http://www.download.com/Microsoft-Zune-Theme/3000-2420_4-10818187.html It's a great color combo, and I highly advise it.

From Download.com's editor review:

Microsoft's takes a decidedly dark turn in this black-tinted theme for Windows XP. A bright orange Start box, sharp gradients, and effective gray-on-gray accents make the theme--based on the company's Zune media player--a welcome change from the default blues and greens. We're not especially enamored of the default desktop wallpaper, which lunges away from the cool factor generated by the rest of the theme in favor of cheesiness, but that's an easy enough user customization. The theme looks especially good when coupled with the Firefox Zune theme created by an independent developer.

Here's a preview of what it looks like on my desktop if your interested: http://i265.photobucket.com/albums/ii229/Soccerfreak1334/Zune-1.jpg