[PHP] Creating a Directory

[PartyPosters]

Hello, I am using the following script to upload files to my server. Is there 
anyway I can create a directory (on the fly) for the new image to go, as I want 
people to be able to upload files with the same name.


Thanks

$uploadDir = 'uploads/';
$uploadFile = $uploadDir . $_FILES['form_data']['name'];
print "<pre>";
if (move_uploaded_file($_FILES['form_data']['tmp_name'], $uploadFile))
{
    print "File is valid, and was successfully uploaded. ";
   # print "Here's some more debugging info:\n";
    #print_r($_FILES);
}
else
{
 print "File is invalid. ";
   # print "Possible file upload attack!  Here's some debugging info:\n";
 #   print_r($_FILES);
}
print "</pre>";