:hover all the way, until you until to do it on something other than a link tag,

then you need this:
Whatever:hover

ps.: Karinne, there's an error (I think) on you tutorial:

1. #nav a.home {
2. background: url('home.jpg') no-repeat 0 0;
3. }
4. #nav a.home:hover {
5. class="tab1"background-position: 0 -40px;
6. }