Comment: Docbook to PDF is XSLT and then FOP (Score 1) on 2009.10.23 17:26
Docbook XSLT stylesheets are available as the docbook-xsl package in fink. FOP you have to download from apache.org but it's Java and it works fine on OS X.
I do a lot of docbook work and so have put together lots of wee makefiles to do this conversion for me.
See something like http://github.com/simoncozens/songbee/blob/master/manual/Makefile for one of them. If you can't get FOP working, then the latexpdf target will do it through latex.