[PERFORM] Postgresql educational sources

[Nid]

Rather than ask some general, unanswerable question on how to tune my database...I thought I ask where I might find an introduction to...or manual/tutorial for the depths of managing a postgres db.  Books?  Websites?  Assume a basic to intermediate knowledge of DBs in general with a desire to learn about postgres from the ground up.  If it makes a difference I'm using a postgres db in a Red Hat Linux OS environment.  Thanks!   nid