411 REFERENCE · Wikibooks
WebObjects/Database Compatibility and Comparisons/Postgresql
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Yes, PostgreSQL does work with WebObjects. The best place to start is the Project WONDER PostgresqlPlugin Page.
If you're on a Mac, Apple has an article on installing PostgreSQL on Mac OS X that is pretty straightforward.
If you're interested in a nice graphical interface to managing your PostgreSQL installation, you may want to checkout out Navicat PostgreSQL from Navicat.