has anybody put this together yet?
or have a good idea where to start?

Ideally want this working on both desktop (osx/win/nix) and iphone

personally would settle for osx/iphone objective-c. but ideally want a cross platform c++ implementation.

p.s. note ofxAvahi : http://forum.openframeworks.cc/t/ofxavahi/7312/1
(avahi gives you ‘bonjour’ on systems without bonjour installed, i.e. not ios/osx/windows if bonjour’s installed)

It seems NSNetService and NSNetBrowser is what you need:

I guess NSNetService allows to publish services and NSNetBrowser to discover them.

If you implement the addon it would be great to have a similar api as ofxAvahi, then we can make ofxZeroConf following the swappable api pattern we are using in other parts of OF like the videoplayer, grabber…