To load the TINY MCE on a specific page, use the following function on the Adminhtml Edit block of your module:
protected function _prepareLayout() {
parent::_prepareLayout();
if (Mage::getSingleton('cms/wysiwyg_config')->isEnabled()) {
$this->getLayout()->getBlock('head')->setCanLoadTinyMce(true);
}
}
To enable the editor for a certain editable textfield, just use 'wysiwyg' => true, instead of 'wysiwyg' => false. i.e.:
$fieldset->addField('description', 'editor', array(
'name' => 'description',
'label' => Mage::helper('sevents')->__('Description'),
'title' => Mage::helper('sevents')->__('Description'),
'style' => 'height:12em;width:500px;',
'wysiwyg' => true,
'required' => true,
));