You can cancel the pay-as-you-go the next day but you won't get a refund...all you'll do by canceling is ensuring that next month it isn't automatically charged to your credit card. You'll also have no cell service in Canada or data so there isn't an easy way to deplete your prepaid minutes which will expire 30 days from signup. Fortunately I had a trip to California to burn through most of my minutes and use a ton of 'unlimited' data.
You won't be able to use your Canadian iTunes account to activate it...you'll need to use a US one along with a valid US address and US credit card (unless you've had a US address added to your Canadian card which I've heard has also worked).
As for it working indefinitely, nobody knows for sure yet as there hasn't been any updates from Apple yet.
My current minutes expire on August 13th so if an update comes after that date, I'll post here if my iPhone still works or not
You won't be able to use your Canadian iTunes account to activate it...you'll need to use a US one along with a valid US address and US credit card (unless you've had a US address added to your Canadian card which I've heard has also worked).
As for it working indefinitely, nobody knows for sure yet as there hasn't been any updates from Apple yet.
My current minutes expire on August 13th so if an update comes after that date, I'll post here if my iPhone still works or not