插件

Login only catalog

his small extension requires a customer to be logged in order to view products or product collections.

http://www.magentocommerce.com/magento-connect/site-management/catalog/login-only-catalog.html

Groups Catalog

Hide categories and products from customers depending on the customer group (for Magento 1.5 and older)

http://www.magentocommerce.com/magento-connect/site-management/catalog/netzarbeiter-groupscatalog.html