I can confirm that this feature does *not* require the iPhone to be on the same wifi network as the other device.
Indeed, it works with the iPhone wifi and bluetooth switched off and the iPhone only connected to the net over cellular!
So you don't even need your phone with you - you could leave it at home when you travel and SMS from overseas via wifi!!
Indeed, it works with the iPhone wifi and bluetooth switched off and the iPhone only connected to the net over cellular!
So you don't even need your phone with you - you could leave it at home when you travel and SMS from overseas via wifi!!