Basic Link Rollover as CSS Sprite

The set height and width ensure only a portion of the sprite.png graphic is shown. The rollover shifts the position of the background image, revealing a different area of the graphic.

a {
   display: block;
   background: url(sprite.png) no-repeat;
   height: 30px;
   width: 250px;
}

a:hover {
   background-position: 0 -30px;
}