Save the following in /Library/LaunchDaemons/net.lighttpd.plist to have lighttpd start automatically on any OS X 10.4 computer. Note that this assumes a working DarwinPorts lighttpd installation (otherwise you will need to change the paths to the lighttpd executable). Note that this also assumes that the lighttpd.conf file is in /opt/local/etc.

<?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">
<plist version="1.0">
<dict>
        <key>Labelkey>
        net.lighttpd</string>
        <key>OnDemandkey>
        />
        <key>Programkey>
        /opt/local/sbin/lighttpdstring>
        ProgramArguments</key>
        <array>
                <string>/opt/local/sbin/lighttpdstring>
                -f/opt/local/etc/lighttpd.confstring>
                -D</string>
        array>
</dict>
plist>