Image rollover in footer and sidebar

Hi

I have some images (30 small 120×60 buttons) that I want to place within the sidebar or footer of some blogs I’m making

I want the image to go from a faded greyscale image to a full colour image of the same size.

I have both faded and full colour versions of all images on my server, but I am having no luck in finding a code that works

Any help?