Beware! Using your cell phone in new places can add hundreds of thousands to your bill. In a recent case, taking a U.S. cell phone into Canada and not even making a single voice call resulted in $201,000 for a single month of charges. In a recent case, the user is deaf and cannot make voice calls. However, he did use it often for text messaging and he used Internet-streaming services while in Canada.
After a lot of television publicity was generated, the cellphone provider agreed to drastically lower the charge to "only" $2,500 and gave the phone's owner six months to pay off the fee. Still, that's a huge fee for something that the user didn't realize in advance would cost thousands of dollars.
You can read more at http://goo.gl/oU2mD
Going to Canada in the RV any time soon? Turn the cell phone off before crossing the border! Even better, use an unlocked GSM cell phone and purchase a Canadian SIM card. See http://goo.gl/RtGT6 for a long list of places that sell Canadian SIM cards. At least you then will pay local charges, not roaming charges. That is, with a Canadian SIM card, you will pay the same fees that Canadians pay, which is still not cheap.
I use an unlocked Aple iPhone 4 that I purchased earlier this year in England. For a recent trip to Canada, I purchased a "pay-as-you-go" Canadian SIM card from an online vendor for $29 and that included a $10 (Canadian) credit towards the first bill. As it turned out, I never used the full $10 on my 4-day trip.
Note: the cell phone must be unlocked and it must be a GSM phone. Most phones sold by the cell phone companies in the U.S. are locked. That is, the phones are only useable on that one company's network. However, unlocked cell phones are available from many online merchants.
GSM is the standard used by most cell phone companies in Europe as well as much of the rest of the world, although not in the U.S. or Canada. In the U.S., only AT&T and T-Mobile use GSM. In Canada, Rogers is the primary GSM provider.
For U.S. residents, that means the only phones that can have a new SIM card installed are those that normally operate on either AT&T or the T-Mobile networks. Phones from Sprint, Verizon, Virgin, and other U.S. providers operate on the CDMA standard, which is not compatible with GSM.
You can purchased unlocked GSM cell phones from any of dozens of online merchants. Purchasing a second phone for your trip to Canada will be a lot cheaper than paying roaming rates when using your primary cell phone in Canada!