Free PostgreSQL Resources
Using PostgreSQL With PHP
This tutorial is very basic, and will provide you with all of the information you'll need to start using PostgreSQL With PHP.
PostgreSQL Mirror Sites
Download the latest versino of PostgreSQL.
PostgreSQL Technical Documentation
Articles and reference materials.
PostgreSQL JDBC Drivers
From here you will get up to date information relating to the JDBC driver for PostgreSQL, download pre-compiled driver in a jar file, and look at current documentation
Professional Linux Programming Part 1 - Accessing PostgreSQL from Code
Mostly C programming examples.
PostgreSQL Referential Integrity
A flash tutorial that can be downloaded and run offline.
Taking E-Business Up a Notch
PostgreSQL article.
PostgreSQL Forum
PostgreSQL forum.