Spritebox is a WYSIWYG tool to help web designers quickly and easily create CSS classes and IDs from a single sprite image. It is based on the principle of using the background-postion property to align areas of a sprite image into block elements of a web page. It was made using a combination of jQuery, CSS3 and HTML5, and it totally free to use.

Requirements: jQuery, CSS3, HTML5
Demo: http://www.spritebox.net/
License: License Free