Hey guys,
thanks to BetaWar I have everything sorted out except one last thing:

As you can see with this image I've added a little sponsors box down the bottom of the main content. I think it looks really ugly so I want to make a new side panel, the same colour as my main content box and move the sponsor details over there.
My code has barely changed, but here it is:
html
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head><title>AI Conference 2009 - Title Page</title>
<LINK rel="stylesheet" type="text/css" name="style1" href="styles/basic.css">
</head>
<body>
<div id="container">
<div id="header">
<div id="headertitle"><span class="conferencetitle">AI Conference 2009</span><br />
<span class="subheader">22nd Australasian Joint Conference on Artificial Intelligence<br />
4~8 December 2009, Hobart, Australia</span></div>
<div id="links"><span><a href="index.html">Home</a></span> | <span><a href="callpaper.html">Call for Paper</a></span> | <span><a href="committee.html">Program Committee</a></span> | <span><a href="http://www.discovertasmania.com/">About Tasmania</a></span> | <span><a href="signup.html">Sign Up</a></span> | <span><a href="signin.html">Sign In</a></span></div>
</div>
<div id="mainbody">
<div class="header1">Welcome to AI 2009</div>
<p class="bodytext">AI 2009 is the 22nd ACS Australian Joint Conference on
Artificial Intelligence. The conference will be held at Wrest
Point Hotel, Hobart. This conference series is Australia's premier
venue for the dissemination of new research in both the theory
and application of artificial intelligence. AI 2006 will be hosted
by the <a href="http://www.utas.edu.au/">University of Tasmania's</a> <a href="http://www.cis.utas.edu.au/cisview/news.jsp">School of Computing</a>, and will
be held in the beautiful city of Hobart, Tasmania, 4th to 8th
December, 2009.</p>
<div class="header1">Announcements</div>
<p class="bodytext">
<u>2009-3-31 :</u><br />
Deadline for expressions of interest in conducting
workshops has been changed from March 31, 2009 to
May 12, 2009.<br />
<br />
<u>2009-3-16 :</u><br />
The 22nd Australian Joint Conference on Artificial
Intelligence (AI 2009) call for expressions of interest in
conducting workshops.<br />
<br />
<u>2009-3-16 :</u><br />
Student scholarship information(see <a href="callpaper.html">Call for Papers</a>)</p><br />
</div>
<img src ="images/bg.gif">
<div id="sidebar">
<div class="padding">
<div class="header1">Sponsors:</div><br />
<a href="http://www.google.com"><img border="0" src="images/google-logo.jpg" width="105" height="70"></a>
<a href="http://www.utas.edu.au"><img border="0" src="images/utas-logo.gif" width="90" height="70"></a></div>
</div>
<div id="footer">Contact: Program Chair (ai09@utas.edu.au)<br />
Australasian Joint Conference on AI©2007-2008 <br />
All Right Reserved </div>
</div>
</body>
</html>
css
body {
font-family: 'Trebuchet MS', Helvetica, sans-serif;
font-size:12px;
margin-top:-2px;
background:url('../images/bg.gif');
}
#container {
margin: 0 auto;
width: 736px;
}
#header {
background:url('../images/header.jpg');
height:116px;
width: 736px;
}
#headertitle {
padding-top:15px;
padding-left: 15px;
float:left; font-size: 1.2em;
color:white;
}
.conferencetitle {
font-size: 1.6em;
font-weight:bold;
padding-left: 5px;
}
.subheader {
color: #c7c6c7;
font-size: 1em;
}
ol, ul{
color:white;
text-indent:30px;
font-size:.9em;
letter-spacing:.2px;
padding: 1px 5px 10px 40px;
}
#links {
padding-top:85px;
padding-left:290px;
color:white;
font-weight:bold;
letter-spacing:.3px
}
#calllinks {
padding-left:15px;
font-size:1em;
color:white;
font-weight:bold;
letter-spacing:.3px
}
a {
color:white;
text-decoration:none;
font-size:.8em;
}
a:hover {
color:red;
text-decoration:none;
}
#mainbody {
background:#3d3d3d;
width:736px;
clear: both;
margin-top:20px;
}
.header1 {
color:white;
font-size:1.2em;
text-indent:20px;
padding-top:10px;
font-weight:bold;
letter-spacing:.3px;
}
.header2 {
text-decoration: underline;
color:white;
font-size:1.2em;
text-indent:20px;
padding-top:10px;
font-weight:bold;
letter-spacing:.3px;
}
.bodytext {
color:white;
font-size:.9em;
letter-spacing:.5px;
padding: 0px 10px 0px 40px;
}
.formtext {
color:white;
padding: 12px 10px 5px 40px;
font-size:.9em;
padding-top:1px;
letter-spacing:.5px;
}
.spantext {
margin-left: 10px;
padding-left: 60px;
padding-right:60px;
width:100%
}
#sidebar {
background:#3d3d3d;
width: 486px;
padding-left: 250px;
padding-bottom:10px;
clear: both;
}
#footer {
font-size:.8em
}
div.form-container { margin: 10px; padding: 5px; background-color: #0000; border: #EEE 1px solid; }
p.legend { margin-bottom: 1em; }
div.form-container form p { margin: 0; }
div.form-container form p.note { margin-left: 170px; font-size: 90%; color: #333; }
div.form-container form fieldset { margin: 10px 0; padding: 10px; border: #DDD 1px solid; }
div.form-container form legend { font-weight: bold; color: white; }
div.form-container form fieldset div { padding: 0.25em 0; }
div.form-container label,
div.form-container span.label { margin-right: 10px; padding-right: 10px; width: 150px; display: block; float: left; text-align: right; position: relative; }
div.form-container label em,
div.form-container span.label em { position: absolute; right: 0; font-size: 120%; font-style: normal; color: #C00; }
div.form-container input:focus,
div.form-container div.controlset label,
div.form-container div.controlset input { display: inline; float: none; }
div.form-container div.controlset div { margin-left: 170px; }
div.form-container div.buttonrow { margin-left: 180px; }