How do I avoid extra charges on my AT&T bill while in Canada?

Turn off data roaming.

See here.

There is a new app out called Beluga that runs on your phone. It does some really cool things but the reason I’m mentioning it, is that you can use it to send a message to someone and if they don’t have Beluga it just arrives as an SMS message and they can reply back.

Do you have Skype on your iPhone? You could use that to make calls and send SMS while on the wifi.

I have Sprint. Before travelling to Canada I called Sprint asked if my service extended into Canada. They gave me the option to pay a few dollars for the days I was in Canada for international calling at a special rate. I don’t remember if the texts were included, or maybe free on the plan? I don’t remember. Just call At&t and find out your options.

You could turn on airplane mode but that would completely disconnect from the carrier meaning you wouldn’t be able to text. iPhones have data roaming off by default now so you shouldn’t be charged for cell data from a carrier (but you can still use wifi and that’s free)