Add new attribute into product catagory in magento and removing the same attribute

In any one of the .PHTML page paste the following code( i.e, app\design\frontend\base\default\template\page )
<?php

$setup = new Mage_Eav_Model_Entity_Setup('core_setup');

// Create input type as "Textbox"

$setup->addAttribute('catalog_category', 'author', array(
    'group'         => 'General',
    'input'         => 'text',
    'type'          => 'varchar',
    'label'         => 'Author',
    'backend'       => '',
    'visible'       => 1,
    'required'      => 0,
    'user_defined' => 1,
    'global'        => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_GLOBAL,
));