In example below I upgraded is_visible_on_front and used_in_product_listing from false to true for two attributes namely flavor and unit_count. These attributes are product attributes and refer to Mage_Catalog_Model_Product::ENTITY or catalog_product.
For update attribute params we are need the: entity id of attribute, id of attribute, field name what we wont to change, new field value and sort order. Function what we will use is updateAttribute from class Mage_Eav_Model_Entity_Setup.
/* @var $installer Mage_Catalog_Model_Resource_Setup */