There are commands to read a directory in PHP...

$dirname='/home/dir-to-read';

if ($handle = opendir($dirname)) {
while (false !== ($filename = readdir($handle))) {
echo($filename."\n");
}
closedir($handle);
}

Would load and print a list on the page. Of course you'd probably want to do some formatting rather than just an echo. You can put whatever code you want there.