How do we find a cell phone plan that will meet our needs when we move to Canada?

One thing to know about Verizon (and any carrier) is that it's actually very easy to switch handsets even if there is no SIM card. You do what's called an "ESN Swap" which you can do online, on the phone or in-store. ESN=electronic serial number. So don't worry about SIM cards. That said, you can generally only swap handsets within the same carrier (i.e. even though Sprint and Verizon use the same type of network, it's difficult/impossible to use a Sprint phone on Verizon). However you do not have to buy your phone from your carrier specifically. You can buy/borrow a phone from a friend, off Craigslist, eBay, whatever. For you, an ideal situation would be to acquire an "unlocked" phone that works on your carrier of choice in both countries.

AT&T uses the same frequencies as the major Canadian carriers (Telus, Bell, Rogers). If you were to get an AT&T cell phone and unlock it, it would be usable on these carriers. T Mobile uses the same frequencies as the budget carriers (Wind, Mobilicity). Again, if you get a T Mobile phone and unlock it, it would be usable on these carriers. I can't help you much in terms of US cell phone plans, but it would seem advisable to not sign any long term contracts at this point. You will be able to get a cell phone from a carrier here when you sign a new contract. Be warned that you will need to sign a 3 year contract to get significant discounts on your phone.

Have you considered the new http://www.nokia.com/us-en/products/lumia/?cid=ncomprod-fw-src-na-ace_0x0-lumiab-google-us-en-1todtmtc75d4e? It's an $100 phone, but At&T offers it for free if you are jumping to it from another company. You have to buy a two year contract, though. That's the only downside. The new Lumia 900 is a phone from Microsoft. It's very sleek and much more beautiful than the iPhone. However, the downside to this phone is that the app store isn't as mature as the Apple app store.

Oh, forgot to add, if you just need a phone for a few months, would grabbing one from Craigslist be an option? Get a deal on a phone with no commitment to a carrier...

Look into Virgin ... talk to the reps at a Virgin Kiosk or Store. I don't know if they can transfer, but they serve both countries, and have a lot of options available. Look at websites for Virgin for both U.S. and Canada to get an idea, then stop in and talk to someone.

FYI, you can get out of most cell phone contracts if you prove you'd moved outside of their service area. On top of that, smartphones in Canada are expensive. Here's what I'd do. I'd buy an iPhone 4S from AT&T, ashttp://thewirecutter.com/reviews/the-iphone-4s-is-the-best-smartphone/, and the AT&T model will work in Canada. As soon as you get to BC, fax your first bill/pay stub/rent check to AT&T, and they'll let you out of your contract. You can get your phone unlocked, and then walk into a Telus/Bell/Rogers shop and pick up a SIM and a new plan.

I don't feel as if I can speak authoritatively to most of your questions, but if Virgin does offer something that works for you, they have month-to-month contracts that include very generous data plans (like, unlimited with 300 talk minutes for $35. The next step up, in the minute range, 1200, I think is $45). Some of their basic android phones can be had for under $100. The rest of the details though, I'm not sure.

Happy Virgin Mobile customer here; I doubt the phones will work in Canada, but 1) they're not that expensive and 2) you always can resell them before you leave (I sold my previous VM phone on one of those sell-back sites and got about half what I'd paid for it a year before). Or you could even hang on to one of the phones for when you are visiting the States. AT&T and T-Mobile both have prepaid options but the phone choices are not as good as for their contract plans. And the prepaid plans are more expensive than Virgin's plans. If it was me, though, I'd tough it out with the old crappy phone for another six months. You can do it!

Thanks for all the useful info folks! I will do some digging =)