This is a Preferances plugin which is visible in your network as a full uPnP Server.
You can share Aperture/iTunes/iPhoto and folders of your choice. Also registering of devices being able to connect you is possible. I use it to play movies or podcasts in HD on my TV without any cables. Watching the iPhoto Library with all Events and Albums on your PS3 or simple downloading some data to your PS3 from your mac.
Mac OS X 10.5 or later.