[curtiss]

The way you have it set up right now, you don't need javascript to accomplish what you want. You just need CSS.

Look into the :hover property.

#menu .about {
width: 161px;
height: 34px;
background: url(images/About.png) no-repeat;
left: 0px;
top: 0px;
}

#menu .about span {
width: 161px;
height: 34px;
background: url(images/AboutOver.png) no-repeat;
left: 0px;
top: 0px;
}

Would become:

#menu a.about {
width: 161px;
height: 34px;
left: 0px;
top: 0px;
}

#menu a.about:link, #menu a.about:visited {
background: url(images/About.png) no-repeat;
}

#menu a.about:hover {
background: url(images/AboutOver.png) no-repeat;
}