Hi!

With commit #1019443 to kdebase/runtime/kioslave/network (done today) I added a new entry for "Plasma service" to the DNSSD (zeroconf) backend for the network:/ kioslave, which means that network:/ should now show a nice Plasma icon for such services and have a link "plasma:/hostname:port/name" connected to the entry.
(Beware, you need to restart kded after updating your install, as the kioslave is feeded by a kded module, which has the data in the binary (yes, TODO :) )! Perhaps you even have to load the module manually, the automatic load is reported to sometimes fail:
"qdbus org.kde.kded /kded loadModule networkwatcher").

Now, the listing in network:/ is one thing, one also wants to deal with the service item in Konqueror, e.g. click on it or drag'n'drop it to the Plasma workspace. The same happens if the plasma:/ url is used in web pages or emails ("Son, here you can connect to my Dinner-is-ready plasmoid, Yours, Mum"), or isn't this supposed to be done?
With KIO there is the need of a .protocol file which describes what the plasma:/ protocol is about (see patch for prototype). AFAIK for such protocols not starting a kioslave, but a helper program ("helper=true"), that one needs to be defined here in the "exec=" line. So what would the helper program be for plasma:/ urls? For Drag'nDrops this entry is ignored, BTW, and just the url passed.