$uploaddir = "images/";
$uploadfile = $uploaddir . basename( $_FILES[ 'file' ][ 'name' ] );
echo '<pre>';
if( move_uploaded_file( $_FILES[ 'file' ][ 'tmp_name' ], $uploadfile ) )
{
    echo "File is valid, and was successfully uploaded.\n";
}
else
{
    echo "Possible file upload attack!\n";
}
echo "Here is some more debugging info:";
print_r( $_FILES );