Aligning Div content to top

I have the following div, which I want to align to the top-left of the browser:

<body onload="javascript:setDefaults();">
  <div class="top">
             <img alt="foo" src="foo.gif" align="left" border="0" />
             <p class="headers">
                 <b>Header title</b>
             </p>
             <p class="headers">other header stuff</p>
  </div>
<!-- ...more code... /-->

The affiliated css is:


        div.top {
            top: 0px;
            width: 750px;
            height: 100px;
            background-color: #FFFFFF;
        }

In IE6 it properly aligns it to the top, but in FF there is a gap between the top of the browser and the top of the tab – I’d guess approximately 20px.