Will AT&T and TMobile phones work in Canada?

[kittshelby]

Here in Vancouver Canada, there are very few posts on craigslist for Nokia 920 or HTC 8X and the ones that are there are selling for high prices ($500 plus). So I'm thinking of going down to Seattle, since I'm so close to the border, to buy a 920 or 8X on Craigslist during the holidays.

Does anyone know if the AT&T phones, or TMobile (I might get the 810 too), will work in Canada. For example, with Rogers. If not, will unlocking it make it work?

Has anyone done this?

Thanks