Group access extension:
JUGA is Joomla component that allows you additional control over what content is available to which users. It is NOT A HACK (like JACL); JUGA installs and uninstalls *easily* as a component. To activate/de-activate it, install and publish/unpublish the JUGA Mambot. After installing JUGA, merely synchronize it's table with your site's components and content. Then, define which items each group has access to. After assigning users to JUGA groups, activate the Mambot and voila!