Wow. I'm on my way from Seoul to Seattle and have my laptop plugged into a power outlet under my seat and have broadband access (for free). I just tried skype-ing my wife's cellphone and was able to get a pretty damn clear connection, except that I'm guessing she heard a lot of white noise from the cabin noise.
That's pretty damn cool!
It's called Connexion By Boeing. Although it's free I was required to enter credit card information to use the service. Interestingly though, there were other payment options including what looked like tie-ups with telecom companies (maybe this gets tagged onto your monthly phone bill?)