[gtuhl]

Thought I was add that the PostgreSQL documentation is really, really good for learning. It is a bit dense but overall very well written, includes nontrivial examples, and you can really get a solid dive into a topic reading it.

The current 8.3 documentation is here: http://www.postgresql.org/docs/8.3/static/

I especially enjoy the sections on indexes: http://www.postgresql.org/docs/8.3/static/indexes.html