A different approach: Where to learn?

Hi all,
after eight years of using MySQL I learned about pgsql and I'm evaluating if it's the case to use it on a new coming project where reliability is a must.

I've seen that pgsql is a DBMS that is "object oriented", that's mean that the data can be organized not only as tables with data to join on relations but also on object that can simplify the management of "real world data": WOW!

I searched on Amazon for books explaining how to unleash the full power of an "object oriented data base" but I've found books explaining the basic of SQL (how to select, how to insert, joins between tables) that are concepts that I already know; I think that a revolutionary product like pgsql is, needs a different approach on design and query; now the question:

Can you suggest books and / or websites where this different approach (if needed) can be learn? Is my idea about this "different approach" totally wrong and pgsql is not so different than other DBMS?

Thanks a lot.
Francesco