CSS: Change background-image on link mouseover

Hi.

I have just recently begun working with CSS. Is it possible with CSS (and without the use of any JavaScript) to have the background image change on a link mouseover?

I have the first image below (blue.jpg) set as my default background image and would like the second image (blue1.jpg) to display when the user hovers over a particular link.

URL
URL

Thanks for any help anyone can offer

a:link {
background-image: url(a.jpg);
}
a:visited {
background-image: url(a.jpg);
}
a:hover {
background-image: url(b.jpg);
}
You can change other attributes too.

Make sure a:hover goes after a:visited or you will see
problems in Netscape.