function sortByChangeTime($file1, $file2)
{
    return (filectime($file1) < filectime($file2)); 
}
$files = glob('*.*');              // use scandir if you want hidden files too
usort($files, 'sortByChangeTime'); // sort by callback
var_dump($files);                  // dump sorted file list
 
//ALTERNATIVE VERSION
 
if($h = opendir($dir)) {
  $files = array();
  while(($file = readdir($h) !== FALSE)
    $files[] = stat($file);
 
  // do the sort
  usort($files, 'your_sorting_function');
 
  // do something with the files
  foreach($files as $file) {
    echo htmlspecialchars($file);
  }
}