CSS center content inside div

Question

I need to center html content inside a div class="partners" (top div with 2 images). As you can see from the image below (it floats left instead of center of the div):

This is my html code:

<div id="partners">
    <div class="wrap clearfix">
        <h2>Partnertnerzy serwisu:</h2>
        <ul>
            <li><a href="http://www.dilbert.com/"><img width="56" height="16" alt="Parnter bar wika" src="/as/partners/wika.png"></a></li>    
            <li><a href="http://www.youtube.com><img width="65" height="15" alt="Parnter bar siemens" src="/as/partners/siemens.png"></a></li>    
        </ul>
        <a class="linkClose" href="/firmy?clbp=1">Zamknij </a>
    </div>
</div>

Image:

CSS:

#partners, #top {
    position: relative;
    z-index: 100;
}
#partners {
    margin: 12px 0 3px;
    text-align: center;
}
.clearfix:after, .row:after {
    clear: both;
    content: ".";
    display: block;
    height: 0;
    visibility: hidden;
}
#partners .wrap {
    width: 655px;
}
.wrap {
    margin: 0 auto;
    position: relative;
    width: 990px;
}
#partners h2 {
    color: #A6A5A5;
    float: left;
    font-weight: normal;
    margin: 2px 15px 0 0;
}
#partners ul {
    float: left;
}
ul {
    list-style-position: outside;
    list-style-type: none;
}

Answer 1

To center a div, set it's width to some value and add margin: auto.

#partners .wrap {
    width: 655px;
    margin: auto;
}

EDIT, you want to center the div contents, not the div itself. You need to change display property of h2, ul and li to inline, and remove the float: left.

#partners li, ul, h2 {
    display: inline;
    float: none;
}

Then, they will be layed out like normal text elements, and aligned according to text-align property of their container, which is what you want.