One of the main arguments presented against Google Apps in the enterprise is a lack of the ability to implement policy controls and fine grained permissions to data. And to a certain extent, this holds true. For example, you cannot share contacts with specific groups, Google Apps Sync does not allow you shared group calendars within Outlook, there are no shared tasks and so on.
But in its continuing effort to make its suite more robust, and incorporate feedback, Google just introduced new sharing options within Google Docs. The new options are as follows:-

