I am using the code listed on the following link:
http://www.magentocommerce.com/wiki/5_-_modules_and_development/catalog/programmatically_adding_attributes_and_att
There is an easier one-liner for this. Just extend Mage_Eav_Model_Entity_Setup for your install script and use something like this in your installer:
$installer = $this;
/* @var $installer Mage_Eav_Model_Entity_Setup */
$installer->startSetup();
$installer->addAttributeSet(Mage_Catalog_Model_Product::ENTITY, 'New Attribute Set Name');
$installer->endSetup();