Request new password form id
Note that print_r will be better in this case because to see the form he desires one must be logged out otherwise you'll get the password reset for the active user, which is different.

Leandros, try putting this in your theme's template.php and visiting user/password (not logged in)

function YOURTHEMENAME_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  switch ($form_id) {
    case 'user_pass':
        print '&lt;pre&gt;';print_r($form); print '&lt;/pre&gt;';
      break; 
  }
}


It will give you an array of everything that's in there.  Then, say you wanted to change the text "Username or e-mail address" and the text on the submit button you could do this:

function YOURTHEMENAME_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  switch ($form_id) {
    case 'user_pass':
        //print '&lt;pre&gt;';print_r($form); print '&lt;/pre&gt;';
        $form['name']['#title'] = 'Please type your username/email quickly.';
        $form['actions']['submit']['#value'] = 'Email it to me!';
      break; 
  }
}