AJAX submitted form redirection
I had the same situation: ajax login/register form until the fields are correctly filled, and then redirect the user to the logged in section.
This is what I used, and it works fine for me, in the ajax callback function:

ctools_include('ajax');
ctools_add_js('ajax-responder');

$commands[] = ctools_ajax_command_redirect('&lt;front&gt;');

return array('#type' =&gt; 'ajax', '#commands' =&gt; $commands);


the full function looks like this:

function ajax_signup_detailed_submit_callback($form, &amp;$form_state)
{
  $commands = array();
  $messages = drupal_get_messages(NULL, FALSE);

  if (count($messages))
  {
    $commands[] = ajax_command_replace("#better-messages-wrapper", theme('status_messages'));
  }
  else
  {
    ctools_include('ajax');
    ctools_add_js('ajax-responder');
    $commands[] = ctools_ajax_command_redirect('&lt;front&gt;');
  }

  return array('#type' =&gt; 'ajax', '#commands' =&gt; $commands);
}


Hope this helps,
Istvan