#nav ul {
width: 100%;
margin: 0px auto;
padding: 0px auto;
text-align: center;
}
#nav li {
border-left: 1px solid #8e8e8e;
border-right: 1px solid #8e8e8e;
display: inline;
list-style-type: none;
}
#nav ul li a{
color: #000000;
text-decoration: none;
font-family: Arial, Verdana, Sans-Serif;
font-size: 0.8em;
padding: 2px 20px 0px 20px;
}
IE7 is fully compliant with CSS. IE6 however, isnt. It will handle roll overs like above but will blow you out when you try drop down menus, etc.
http://www.alvit.de/css-showcase/css-navigation-techniques-showcase.php
Also, try and keep the site validated as you go. Its got a lot of errors already, and doing it as you go makes life a lot easier.
For instance, you are missing info in your < img > tags, and you are also using '&' instead of the correct HTML code #amp;.
http://validator.w3.org/