Image Greyscale with CSS & re-color on mouse-over?

Question

I am looking to take an icon that is colored (and will be a link) and turn it greyscale until the user places their mouse over the icon (where it would then color the image)

Answer 1

Here's a demo. Even works in IE7:

http://james.padolsey.com/demos/grayscale/

and

http://james.padolsey.com/javascript/grayscaling-in-non-ie-browsers/