Today I installed PostgreSQL on my iBook. I used the very good how-to on the Apple site, but it's not complete. It does not describe how to startup (and shutdown) the database automatically. So I wrote a little addition to the page which explains those steps in detail.
[robg adds: I haven't tested this one.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050417184714865