Added Flame

Bonjour has been described as "no-pain networking". If you've ever used iTunes and seen shared libraries popping up without having to configure anything, then you'll know that it really is painless. That's not to say that it's perfect. If you see someone's sharing their music, how do you see if they're also sharing photos with iPhoto? Just start Flame to see all the computers on the network that are advertising services. (If it can, it'll identify the user of each computer instead of giving you the machine's name.) Disclose the services available from each. You can even delve right into the service record to see the gory details, if you like that sort of thing.