Nice system you've got. I feel inclined to warn you and Australians that this service will probably incur you a fee per callback. Here in Australia we have a system where simply dialing a number incurs a fee, known as a "flagfall".
Ah, that's a pity. I might try it when I fly next. Wish there was a website that displayed the airline along with which different tunnelling methods worked. I'd pay for that :)
This is great! Any chance of making it so that it can use email instead of SMS in the mobile app though? SMS gets expensive really quickly in Australia. Thanks again! :)