Use wp_editor()
. There are many configuration options; you have to read the source to get all of them.
Example:
$editor_settings = array (
'textarea_rows' => 15,
'media_buttons' => FALSE,
'teeny' => TRUE,
'tinymce' => TRUE,
'dfw' => FALSE,
);
$content = $get_option( 'your_option_name' );
wp_editor( $content, 'your_editor_id', $editor_settings );