Using MacPorts, I installed Apache2, SVN, SSL etc.
With a WebDAV repository setup, I needed a way to broadcast it's URL over the local subnet using Bonjour, ironically for a Mac there did not seem to be a way to do it.
MacOS Client comes with a Bonjour Module for Apache 1.3, MacOSX Server comes with one for Apache2 (but I do not have it).
Linux can use mod_dnssd but as it is based on Avahi, I am pretty sure it won't work on MacOSX.
A bit of Googling and I found the dns-sd command. The man page says it is designed for testing only, but it seems to work fine, fired off once at startup.
I use this plist, placed in /Library/LaunchDaemons/
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">