You’re developing a Magento importer and you want to clean your DB after some tests? Here you have:

require_once dirname(__FILE__) . '/app/Mage.php';
Mage::app()->setCurrentStore(Mage::getModel('core/store')->load(Mage_Core_Model_App::ADMIN_STORE_ID));

$resource = Mage::getSingleton('core/resource');
$db_read = $resource->getConnection('core_read');

$attribute_sets = $db_read->fetchCol("SELECT attribute_set_id FROM " . $resource->getTableName("eav_attribute_set") . " WHERE attribute_set_id<> 4 AND entity_type_id=4");
foreach ($attribute_sets as $attribute_set_id) {
	try {
		Mage::getModel("eav/entity_attribute_set")->load($attribute_set_id)->delete();
	} catch (Exception $e) {
		echo $e->getMessage() . "\n";
	}
}

Note that only products’ attribute sets are deleted, those are often generated automatically during imports.