XNAGameStudio/Samples/SpriteSheetSample_4_0/SpriteSheetSample/SpriteSheetSampleContent/SpriteSheet.xml

<?xml version="1.0" encoding="utf-8" ?>
<XnaContent>
  <Asset Type="System.String[]">
    <Item>cat.tga</Item>
    <Item>glow1.png</Item>
    <Item>glow2.png</Item>
    <Item>glow3.png</Item>
    <Item>glow4.png</Item>
    <Item>glow5.png</Item>
    <Item>glow6.png</Item>
    <Item>glow7.png</Item>
  </Asset>
</XnaContent>