We were on a flight (southwest) in which my friend and I sat at different parts of the plane, and thought it would be useful to be able to text each other over bluetooth. It would be nice to have some form of a bluetooth texting instead of this morse code feature.
Also, we couldnt get a voice conversation working over an iPhone 3GS and a 3rd Gen iPod Touch with the apple earbuds which have an inline mic, which works with skype.
Also for the people that want Push Notifications, I dont think it would work unless both devices are connected to the internet, either via the cell phone network or Wifi, maybe iphone 4.0 local notifications could somehow be implemented once it is out.
jevans.900 about Bluetooth Phone