I have centered your website in IE and fixed at least ten errors.
Both
<img src="image"> and
</br> are incorrect for two important reasons.
BR is a single tag, it does not open and it does not close so there is no need to open it with a forward slash.
IMG and
BR are both self closing tags, meaning you do not need another tag to close (
<p> Text </p>).
The correct forms are
<img src="image" /> and
<br /><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-type" content="text/html;charset=UTF-8"/>
<link rel="stylesheet" type="text/css" href="style/style.css"/>
<title>The Ad Place</title>
</head>
<body>
<div align="center">
<div id="wrapper">
<div id="header"> <img src="style/images/header.png" id="logo" alt="Ad Place"/>
<div id="navbar"> <a href="index.php">Home </a> <a href="prov.php">Providers </a> <a href="adv.php">Advertisers </a> <a href="abo.php">About Us </a> </div>
<br/>
<div align="center">
<script type="text/javascript"><!--
google_ad_client = "pub-9821635504472704";
google_ad_slot = "5060944755";
google_ad_width = 468;
google_ad_height = 15;
//-->
</script>
<script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
</div>
</div>
<div id="content">
<h2>Welcome! </h2>
<p> Welcome to Ad Place! We provide free information on what ad providers there are and what they will do for you! We hope this information will help you make the best of your site and make some money! </p>
<p> Please feel free to browse the site and check out all our different areas of the site. We hope the information provided is helpful!You can view my contact information below! </p>
<h2>Rating Sites </h2>
<p>On the site we also have a rating system! You are free to vote for each site once! So if you have used one of the sites on here please rate it on your experience you had with them! </p>
<h2>Contact </h2>
<p> Email: <a href="mailto:greg.froning@bobhoil.com">greg.froning@bobhoil.com </a> </p>
</div>
<div id="affiliates">
<ul id="aff">
<li> <a href="http://bobhoil.com/"> <img src="style/images/bobhoil.png" alt="BobHoil.com!"/> </a> </li>
<li> <a href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=7042524"> <img src="http://bobhoil.com/donatebuts/donate.png" alt="Donate"/> </a> </li>
<li> <a href="http://www.110mb.com/aff.php?un=bobhoil"> <img src="style/images/110.png" alt="110mb.com Free Hosting!"/> </a> </li>
</ul>
</div>
<br/>
<div align="center">
<script type="text/javascript"><!--
google_ad_client = "pub-9821635504472704";
google_ad_slot = "3500610466";
google_ad_width = 468;
google_ad_height = 60;
//-->
</script>
<script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js">
</script>
</div>
<div id="footer">
<p>© Ad Place 2008 Design Created by: <a href="http://bobhoil.com/">bobhoil.com </a> </p>
</div>
</div>
</div>
</body>
</html>
