Используем следующий код:
Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);
$staticBlock = array(
'title' => 'My Static Block',
'identifier' => 'my-static-block',
'content' => 'Lorem ipsum',
'is_active' => 1,
'stores' => array(1)
);
Mage::getModel('cms/block')->setData($staticBlock)->save();