Some code change:
<strong><table style='height: 100%; width: 100%;'>
<tr>
<td align='center' ></strong>
<div id='styled_popup' name='styled_popup' style='border:1px solid #000000; width: 380px; height: 300px; display:none; position: relative; zoom: 1'>
<table width='380' cellpadding='0' cellspacing='0' border='0'>
<tr>
<td><img height='23' width='356' src='images/x11_title.gif'></td>
<td><a href='javascript<b></b>:fadeOutMyPopup();'><img height='23' width='24' src='images/x11_close.gif' border='0'></a></td>
</tr>
<tr><td colspan='2' style='background: url("images/x11_body.gif") no-repeat top left; width: 380px; height: 277px;'>
<div align="center">
<form action="freeoffer_thanks.asp" method="post">
<table width="250" border="0" cellspacing="2" cellpadding="0">
<tr>
<td colspan="2" align="center"><span class="pageheader">Sign Up to Learn About
Your FREE $50 Gift</span>
</td>
</tr>
<tr>
<td width="6%" class="text" align="center"><strong>Name:</strong></td>
<td width="94%" align="center"><input name="Name" type="text" size="25" /></td>
</tr>
<tr>
<td class="text" align="center"><strong>Email:</strong></td>
<td align="center"><input name="Email" type="text" size="25" /></td>
</tr>
<tr>
<td class="text" align="center"><strong>Phone:</strong></td>
<td align="center"><input name="Phone" type="text" size="25" /></td>
</tr>
<tr>
<td colspan="2" align="center">
<label>
<input type="submit" name="Submit" value="Submit">
</label></td>
</tr>
</table>
</form>
</div>
</td></tr>
</table>
</div>
<strong></td>
</tr>
</table></strong> This will bring ur popup in middle.