startSetup();
$setup = new Mage_Eav_Model_Entity_Setup('core_setup');

// adding attribute group
$group_name = 'Module Attributes';
$setup->addAttributeGroup('catalog_product', 'Default', $group_name, 1000);

$setup->addAttribute('catalog_product', 'module_attribute_code', array(
        'backend'       => '',
        'source'        => '',
        'label'         => 'Module Attribute Label',
        'group'			=> $group_name,
        'input'         => 'select',
        'class'         => '',
        'global'        => true,
        'visible'       => true,
        'required'      => false,
        'user_defined'  => false,
        'default'       => '',
        'visible_on_front' => false
    )); 		

$installer->endSetup();
?>