How can I theme the Views Exposed Filter?
Exposed filters use the form API, so you can implement a hook_form_FORM_ID_alter():

function MYMODULE_form_views_exposed_form_alter(&amp;$form, &amp;$form_state) {
  $view = $form_state['view'];

  if ($view-&gt;name == 'my_view' &amp;&amp; $view-&gt;display == 'my_display') {
    // do something awesome
  }
}


Normal Form API procedures then apply.