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

Asked by sferik (6121) December 28th, 2010 from iPhone

I’m worried that my iPhone’s plan doesn’t cover text, data, and voice calls in Canada. How much extra does it cost for each? I would like to send a few text messages on New Years Eve and connect to my hotel’s WiFi, but I’d like to avoid paying extra for push/background services. Can I just turn on airplane mode?