Forget your worries about smatphones and roaming data charges. My HTC (other brands are available) roamed 0 bytes of data while in Sweden for 3 day but..
It is allowing me to read CCE and type this mid air over Norway!
Well done to Norwegian for doing free WiFi on board and good by rip-off-roaming charges.
One complaint though. Cycle streets can't find a way home for me.