LaunchDaemons are the new "init" for Mac OS X 10.4 onward.
I have successfully used it to start and run OpenVPN on Mac OS X 10.4 Server.
Below is the .plist file I created to start and run OpenVPN on Mac OS X 10.4
Label
org.openvpn
OnDemand
Program
/usr/local/sbin/openvpn
ProgramArguments
openvpn
--config
openvpn.conf
RunAtLoad
...
