<form action="upload.php" method="post"
 enctype="multipart/form-data" name="upload">
<input type="file" name="userfile"><input type="submit" name="upload" value="Upload">
</form>
<?php
if($_POST['upload'])
{
    // Zielordner
    $ordner = "upload";
    // Dateiname beibehalten
    $dateiname = $_FILES['userfile']['name'];
    // Datei in Zielordner verschieben
    move_uploaded_file($_FILES['userfile']['tmp_name'], $ordner."/".$dateiname);
}
?>