Hello,
Sarah's option should work well for you. Lots of Canadians do use this US service. Expensive though.
I ordered one and used my friend's US address for shipping and picked it up there, so I save around US$150 somewhere there.
It should work well in OZ with wifi, not with future 3G feature, not yet until their international edition comes out.
If voltage is an issue, you can always use an adapter.
Edge's voltage is 110 volts, although I don't see it in specs. page.