<timer_setup>
            <setup>
                <module>Apptha_Timer</module>
                <class>Apptha_Timer_Model_Resource_Eav_Mysql4_Setup</class>
            </setup>

            <connection>
                <use>core_setup</use>
            </connection>
        </timer_setup>

$installer = $this;

$setup = new Mage_Eav_Model_Entity_Setup('core_setup');
$installer->startSetup();

$setup->addAttribute('catalog_product', 'countdown', array(
    'group'                 => 'Prices',
    'label'                 => 'Ativar Cronometro Regressivo',
    'type'                  => 'int',
    'input'                 => 'boolean',
    'default_value_yesno'   => 1,
    'class'                 => '',
    'backend'               => '',
    'frontend'              => '',
    'global'                => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_STORE,
    'visible'               => true,
    'required'              => false,
    'user_defined'          => true,
    'searchable'            => false,
    'filterable'            => false,
    'comparable'            => false,
    'visible_on_front'              => true,
    'visible_in_advanced_search'    => false,
    'unique'                => false
));
$installer->endSetup();

class Apptha_Timer_Model_Resource_Eav_Mysql4_Setup extends Mage_Core_Model_Resource_Setup
{

}