How to remove only created hour?
I think you want to have your node show June 12, 2012

If that is the case, you can do this:

function THEME_preprocess_node(&amp;$variables) {
  if ($variables['submitted']) {
    $variables['submitted'] = t('Posted: !datetime', array( '!datetime' =&gt; format_date($variables['node']-&gt;created, 'custom', 'F j, Y')));
  }
}


Here's PHP documentation for date formats: http://php.net/manual/function.date.php