Robert --
In the future, please post all Project Server questions to the
microsoft.public.project.server newsgroup, as this newsgroup is devoted to
questions about the Microsoft Project desktop application only.
To answer your question:
1. The My Organization category gives "blanket" access to all projects,
resources, and views in the Project Server database.
2. The My Direct Reports category gives access only to specific resources
one level below the user in the RBS outline code structure. The information
derived from this Category is used specifically with the Timesheet Approval
process in Project Server.
For detailed information about Project Server security, I would recommend
you purchase our book for Project Server administrators, available for
purchase by clicking either URL in my signature block. Hope this helps.