This CodeLet will add a facbook connect button to your login / registration form. Using the CSS, you can change the appearnce of the login block/page. This CodeLet also uses Ajax login/register module. Please make sure you have all the require modules and libraries installed before you using this CodeLet.

Drupal : Login / register with Facebook connect button
CodeLet
<?php/** * @filesource *  * Different customization & enhancements to existing features for Channel portal *  * @param $form * @param $form_state * @param $form_id * DrupalD <http://twitter.com/DrupalD> *//** * Implementation of hook_form_alter *  * @param $form * @param $form_state * @param $form_id * DrupalD <http://twitter.com/DrupalD> */function channel_utils_form_alter(&$form, &$form_state, $form_id) {  $user_profile = fbconnect_user_profile();  $op = $user_profile ? 'login' : 'register';  switch ($form_id) {    case 'user_register_form':    case 'user_login':        drupal_add_css(drupal_get_path('module', 'channel_utils') .'/fbappear.css');      $attr = array();      if (variable_get('fbconnect_fast_reg', 0) && variable_get('fbconnect_reg_options', 0)) {        $attr = array('perms' => 'email');      }      $ss__facebook_connect = fbconnect_render_button($attr);      $form['login_text'] = array(        '#markup' => '<h21>Log in instantly with Facebook</h2>',        '#weight' => -50,      );      $form['fbconnect_button'] = array(        '#type' => 'item',        '#prefix' => '<div id="fbbutton">',        '#title' => t('Facebook login'),        '#markup' => $ss__facebook_connect,        '#weight' => -49,      );            $form['points_text'] = array(        '#markup' => '<li>Share what you love with your friends</li>                      <li>See the videos your friends want to share</li>                      <li>Improve your recommendations</li>',        '#prefix' => '<ul>',        '#suffix' => '</ul></div>',        '#weight' => -48,              );            $form['fb_divider'] = array(        '#type' => 'item',        '#prefix' => '<div id="login-divider">',        '#markup' => '&nbsp;',        '#suffix' => '</div>',        '#weight' => -47,      );            $form['or'] = array(        '#type' => 'item',        '#prefix' => '<div id="fbor">',        '#markup' => '<h2>'. t('OR') .'</h2>',        '#suffix' => '</div>',        '#weight' => -46,      );            $form['name']['#size'] = 40;      $form['pass']['#size'] = 40;            break;  }}?>
Info file details
name = Channel portal Utilities
description = Customization & enhancements to existing features.
core = 7.x
dependencies[] = fbconnect
package = Channel
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