display contents of directory by letter

[Anon]

how could i modify this tag below so that it only returns the contents of the directory that start with the letter A? then i can figure out the rest of the letters. THANK YOU VERY MUCH

<?
function paulGetFiles($dir) {
$handle = opendir($dir);
while ($file = readdir($handle))
if (($file != ".") && ($file != ".."))

$files[] = $file;
closedir($handle);
sort($files);
return $files;
}

$dir = 'Tabs/Guitar';
$files = paulGetFiles($dir);

print "<H1>$dir</H1>";

foreach ($files as $file)
if (is_dir("$dir/$file"))
echo "<a href=\"$dir/$file\">$file</a><br>";
else
echo $file;

?>