WordPress: Settings Page

<div id="poststuff">
  <form method="post" action="<?php admin_url( 'themes.php?page=theme-settings' ); ?>">
      <?php
      wp_nonce_field( "wptester-settings-page" );

      if ( $pagenow == 'themes.php' && $_GET['page'] == 'theme-settings' ){

          if ( isset ( $_GET['tab'] ) ) $tab = $_GET['tab'];
          else $tab = 'homepage';

          echo '<table class="form-table">';
          switch ( $tab ){
              case 'general' :
                  ?>
                  <tr>
                      <th><label for="wptester_tag_class">Tags with CSS classes:</label></th>
                      <td>
                          <input id="wptester_tag_class" name="wptester_tag_class" type="checkbox" <?php if ( $settings["wptester_tag_class"] ) echo 'checked="checked"'; ?> value="true" />
                          <span class="description">Output each post tag with a specific CSS class using its slug.</span>
                      </td>
                  </tr>

                  <?php
              break;
              case 'footer' :
                  ?>

                  <tr>
                      <th><label for="wptester_ga">Insert tracking code:</label></th>
                      <td>
                          <textarea id="wptester_ga" name="wptester_ga" cols="60" rows="5"><?php echo esc_html( stripslashes( $settings["wptester_ga"] ) ); ?></textarea><br/>
                          <span class="description">Enter your Google Analytics tracking code:</span>
                      </td>
                  </tr>

                  <?php
              break;
              case 'homepage' :
                  ?>

                  <tr>
                      <th><label for="wptester_intro">Introduction</label></th>
                      <td>
                          <textarea id="wptester_intro" name="wptester_intro" cols="60" rows="5" ><?php echo esc_html( stripslashes( $settings["wptester_intro"] ) ); ?></textarea><br/>
                          <span class="description">Enter the introductory text for the home page:</span>
                      </td>
                  </tr>

                  <?php
              break;
          }
          echo '</table>';
      }
      ?>

      <p class="submit" style="clear: both;">
          <input type="submit" name="Submit"  class="button-primary" value="Update Settings" />
          <input type="hidden" name="wptester-settings-submit" value="Y" />
      </p>
  </form>

  <p><?php echo $theme_data['Name'] ?> theme by <a href="http://wpmidia.com.br/">wpmidia</a> | <a href="http://twitter.com/wpmidia">Follow me on Twitter</a>! | Join <a href="http://facebook.com/wpmidia.lab">wpmidia on Facebook</a>!</p>

</div>