Google Apps introduces a features "user policy management" to Premier and Education edition users at no additional charge, that let "administrators segment their users into organizational units and control which apps are enabled or disabled for each group." Organizations can also use this functionality to test apps with pilot users before making widely available.
Ability to toggle services on or off for groups of users can also help customers transition to Google Apps from on-premise environments. For e.g., a business can enable just collaboration tools like Google Docs and Google sites for users who haven't yet moved off old on-premise messaging solutions. Administrators can manage these settings on "Organizations & users" tab in "Next generation" control panel. Alternatively, organizations can mirror their existing LDAP organizational schema using GA Directory Sync or programmatically assign users to organizational units using GA Provisioning API.
More Info: Help Center