You can use date_parse to parse almost any date format into its components. For example:

$date = date_parse("2012-01-02");
var_dump($date);
Will output:

array(12) {
  ["year"]=>
  int(2012)
  ["month"]=>
  int(1)
  ["day"]=>
  int(2)
  ["hour"]=>
  bool(false)