very simple file upload script for multiple files

I need an upload script that will upload multiple files at once.  I need to set the file names to be the same everytime.  So it renames the files after uploading.  I need to upload 5-10 files and have them automatically named 1.gif through 10.gif.   I have a couple of scripts that do this fine for one file at a time but I need to do multiple for a slide show.

Thanks-

Heres what I use now.  If I could some how use a meta refresh after submitting.  

Thanks-

<?php

$site_name = $_SERVER['HTTP_HOST'];
$url_dir = "http://".$_SERVER['HTTP_HOST'].dirname($_SERVER['PHP_SELF']);
$url_this =  "http://".$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF'];

$upload_dir = "../images/";
$upload_url = "http://####";
$message ="";

//create upload_files directory if not exist
//If it does not work, create on your own and change permission.
if (!is_dir("images")) {
      die ("upload_files directory doesn't exist");
}

if ($_FILES['userfile']) {
      $message = do_upload($upload_dir, $upload_url);
}
else {
      $message = "Invalid File Specified. Ignore if you havent clicked upload yet";
}

print $message;

function do_upload($upload_dir, $upload_url) {

      $temp_name = $_FILES['userfile']['tmp_name'];
      $file_name = '1.gif';
      $file_type = $_FILES['userfile']['type'];
      $file_size = $_FILES['userfile']['size'];
      $result    = $_FILES['userfile']['error'];
      $file_url  = $upload_url.$file_name;
      $file_path = $upload_dir.$file_name;

      //File Name Check
    if ( $file_name =="") {
          $message = "Invalid File Name Specified";
          return $message;
    }
    //File Size Check
    else if ( $file_size > 500000) {
        $message = "The file size is over 500K.";
        return $message;
    }
    //File Type Check
    else if ( $file_type == "text/plain" ) {
        $message = "Sorry, You cannot upload any script file" ;
        return $message;
    }

    $result  =  move_uploaded_file($temp_name, $file_path);
    $message = ($result)?"File url <a href=$file_url>$file_url</a><br><img src=$file_url height=\"210\" width=\"210\">" :
                "Somthing is wrong with uploading a file.";

    return $message;
}
?>
<style type="text/css">
<!--
.style1 {
      font-family: Verdana, Arial, Helvetica, sans-serif;
      font-weight: bold;
}
.style2 {font-family: Verdana, Arial, Helvetica, sans-serif}
-->
</style>

<title>Slideshow Upload Page</title><form name="upload" id="upload" ENCTYPE="multipart/form-data" method="post">
  <span class="style1">Upload Slideshow Image<br>
  </span>  
  <input type="file" id="userfile" name="userfile"><br>
  <input type="submit" name="upload" value="Upload">
</form>
<p class="style2">Click Browse to choose the slideshow file (1.gif) on your computer or office network.</p>
<p class="style2">Click Upload</p>
<p class="style2">The image displayed will be in the slideshow on the front page of lulushoponline </p>
<p class="style2"><a href="collage_upload.php">Change Collage Picture</a></p>
<p class="style2"><a href="slideshow_upload.php">Change Slideshow Image</a></p>
<p><span class="style2"><a href="featured_upload.php">Change Featured Items</a></span> </p>