ifplugd is similar to netplug. A few days ago, I wrote a netplug module for baselayout. Writing one for ifplugd was a little more tricky as I had to alter the ifplugd init script a fair bit so they don’t conflict with each other. Luckily, with a few recent baselayout enchancements we can now work out which init scripts launched which daemons via start-stop-daemon calls :)
To make things more consistent with other baselayout modules, you have to specify the exact options you want over the defaults like so ifplugd_eth0="--api-mode=wlan"
Still, I recommend netplug over ifplugd as it’s smaller, lighter and more simple. Oh, and if anyone can get wlan mode to work with ifplugd, please let me know so I can get it working for wep on my prism54 ;)