function read_dir($dir) {
$array = array();
$d = dir($dir);
while (false !== ($entry = $d->read())) {
if($entry!='.' && $entry!='..') {
$entry = $dir.$entry;
if(is_dir($entry)) {
$array = array_merge($array, read_dir($entry.'/'));
} else {
$array[] = $entry;
}
}
}
$d->close();
return $array;
}

Using:
print_r(read_dir('/home/'));