a few html questions...

<?

if(count($_POST)>0) 
{//the form was posted 
  //do your processing here
  $notices[]='Thank you for uploading a file!';
}
?>
<?if(isset($notices)) { ?>
<?  foreach($notices as $notice) { ?>
         <p class="notice"><?=$notice?></p>
<?  } ?>
<?}?>
<b><font size=3>File Upload</font><br></b><br>
<img src="pics/dl.gif">
Select a file to upload:<br>

<form action="uploadfile.php" method="post" enctype="multipart/form-data">
<input type="file" name="file" size="45">
<br>
<br>
By Pressing Submit, you agree that this file is none of the following:<br>
<ul>
<li>Pornography
<li>Virus(s), Spyware, Adware or keyloggers.
<li>Illegal or copyrighed material
<li>You have been warned<br>
<input type="submit" value="Upload File">
</form>

<p>Your IP is <?=$_SERVER['REMOTE_ADDR'];?></p>

$str = get_file_contents ("mytemplated.html");
ReplaceTemplatesWithData ($str, $data);
echo $str;

Please enter your user details to log-in here...<br>

 <form action = "authenticate.php" method = "post">
 Username:<br>
 <input type = "text" name = "username">
 <br><br>
 Password:<br>
 <input type = "text" name = "password">
 <br><br>
 <input type = "submit" value = "Log In">
 </form>

if(count($_POST)>0)
{

//authenticate code here

}
else
{
//login code here
}