[PHP] uploading a file via php - i need some simple code

[Phil Schwarzmann]

I am having the worst trouble trying to write a tiny simple script that
will upload a file.  Below is my code - can anyone tell me why it's not
working....
 
HTML
 
<form name="form1" method="post" action="upload.php"
enctype="multipart/form-data">
  <input type="hidden" name="MAX_FILE_SIZE" value="1000">
  <input type="file" name="userfile">
  <input type="submit" name="Submit" value="Submit">
</form>
 
PHP (upload.php)
 
$filename = "/test.txt";
if (!move_uploaded_file($userfile, $filename))
{
 echo "something barfed.";
 exit;
}
 
else
{
 echo "uploaded.";
}
 
Something is most likely wrong with the $filename variable.  I don't
know what exactly to put in there.  All I want to do is upload a file
and then move/copy it to a specific directory. 
 
What am I doing wrong?!?!
 
THANKS!!