This is a sample project for using Enterprise Library 5 with ODP.NET
It was tested on Oracle 11g, but it might as well work with different Oracle versions.
You can find a step-by-step configuration and explanation on the blog http://devstuffs.wordpress.com/2012/03/13/enterprise-library-5-with-odp-net/
If you want the SQL scripts, including a stored procedure to list the data, you can download them on http://dl.dropbox.com/u/6963935/samples/EntLib5_ODP.NET/scripts.zip