Using AT&T GoPhone Sim with unlocked Rogers phone?

[taming]

So, I am thinking that if I were to buy a SIM card for the AT&T GoPhone (pay-as-you-go), I could then slip it in my unlocked Magic and purchase paid apps over WiFi from Canada with no phone charges. I'd also have the SIM for travel to the US, of course.

Has anyone tried this?

[evilbaby]

I fairly certain I have heard of people trying this and succeeding but I'm far too lazy to find the links