In this tutorial, create 2 files
1. upload_rename.php
2. upload_rename_ac.php


Steps
1. Create file upload_rename.php.
2. Create file upload_rename_ac.php.
2.1 Create folder "upload" for store uploaded files.
3. CHMOD your upload folder to "777" by using your ftp software(change permission).

############### Code

<table width="500" border="0" align="center" cellpadding="0" cellspacing="1" bgcolor="#CCCCCC">
<tr>
<form action="upload_rename_ac.php" method="post" enctype="multipart/form-data" name="form1" id="form1">
<td>
<table width="100%" border="0" cellpadding="3" cellspacing="1" bgcolor="#FFFFFF">
<tr>
<td><strong>Single File Upload </strong></td>
</tr>
<tr>
<td>Select file
<input name="ufile" type="file" id="ufile" size="50" /></td>
</tr>
<tr>
<td align="center"><input type="submit" name="Submit" value="Upload" /></td>
</tr>
</table>
</td>
</form>
</tr>
</table>

############### Code

<?php

// Your file name you are uploading
$file_name = $HTTP_POST_FILES['ufile']['name'];

// random 4 digit to add to our file name
// some people use date and time in stead of random digit
$random_digit=rand(0000,9999);

//combine random digit to you file name to create new file name
//use dot (.) to combile these two variables

$new_file_name=$random_digit.$file_name;

//set where you want to store files
//in this example we keep file in folder upload
//$new_file_name = new upload file name
//for example upload file name cartoon.gif . $path will be upload/cartoon.gif
$path= "upload/".$new_file_name;
if($ufile !=none)
{
if(copy($HTTP_POST_FILES['ufile']['tmp_name'], $path))
{
echo "Successful<BR/>";

//$new_file_name = new file name
//$HTTP_POST_FILES['ufile']['size'] = file size
//$HTTP_POST_FILES['ufile']['type'] = type of file
echo "File Name :".$new_file_name."<BR/>";
echo "File Size :".$HTTP_POST_FILES['ufile']['size']."<BR/>";
echo "File Type :".$HTTP_POST_FILES['ufile']['type']."<BR/>";
}
else
{
echo "Error";
}
}
?>

This step, do it when you upload to real server. This example, I use WS-FTP, right click at upload folder > FTP Commands > CHMOD(Unix)