Customizing Zune Background
Duncan Mackenzie wrote some tips you need to know for creating backgrounds pictures for your Zune.
As you know Zune screen is 240x320, but also has a little zoom effect when browsing menus, and another size when using TV out. This article describe all you need to know to create an appropriate picture :
http://www.duncanmackenzie.net/blog/creating-backgrounds-for-your-zune/