<?php
$foo = array(
'21-8-2009' => 'foo',
'22-8-2008' => 'bar',
'30-9-2011' => 'baz',
);
uksort($foo, function($a, $b) {
$time_a = strtotime($a);
$time_b = strtotime($b);
if ($time_a == $time_b) {
return 0;
}
if ($time_a > $time_b) {
return 1;
}
return -1;
});
print_r($foo);