GoFuckYourself.com - Adult Webmaster Forum - IE fix for tabbed nav menu?

Hiya, sorry to ask this here but I've done a bit of searching and can't figure out why Windows IE is screwing up my top nav menu.

The relevant CSS

Code:

ul.topnav {

    height:30px;

        list-style:none;

        margin:0px;

        padding:0px;

        display:block;

        width:600px;

        margin:0 auto;

}



ul.topnav li {

        float:left;

        margin:0 1px 0 0;

        background: #EEEEEE url(images/tab.png);

}



ul.topnav a {

        background-image: url(images/tab.png);

    color:#FFFFFF;

    display: block;

    float: left;

    height: 30px;

    padding-left: 20px;

    text-decoration: none;

}



ul.topnav a:hover {

        background-position: 0 -30px;

        color:#222222;

}



ul.topnav a:hover span {

        background-position:100% -30px;

}



ul.topnav span {

        background-image: url(images/tab.png);

        background-position:100% 0;

    display: block;

    height: 20px;

    padding-right: 20px;

        padding-top:10px;

}

the HTML

Code:

<div>

<ul class="topnav">

        <li><a href="index.php" title="Home"><span>Home</span></a></li>

        <li><a href="index.php?cmd=2" title="Submit Your Pictures And Get Rated!"><span>Submit Pictures</span></a></li>

        <li><a href="index.php?cmd=10&amp;ty=1" title="Latest Nude Pictures For You To Rate!"><span>Latest Pics</span></a></li>

        <li><a href="index.php?cmd=10&amp;ty=2" title="Top 10 Pictures As Voted By You Guys!"><span>Top 10</span></a></li>

        <li><a href="index.php?cmd=10&amp;ty=3" title="Top Rated Guys"><span>Top Guys</span></a></li>

        <li><a href="index.php?cmd=10&amp;ty=4" title="Top Rated Girls"><span>Top Girls</span></a></li>

</ul>

</div>

I think it's got something to do with the fact Im using

display: block;
float:left;

instead of

display:inline;

But I don't know any other way to do it? Anyone got a hack for IE? works in FF and safari OSX, and FF Windows.

Thanks