Check out technet.oracle.com, they have the books online etc as MSDN. I worked on a small project 1.5yrs ago with Oracles fine grained access control features and worked very well. The whole idea of the DB re-writing queries and appending a context string to the predicate is very powerful. The other technology was Oracle Labal security where it adds a new column to selected tables and applies a variety of security logic to your app in order to seemlessly implement RLS for existing apps.
Author of "SQL Server Backup, Recovery & Troubleshooting"
Author of "SQL Server 2k for the Oracle DBA"