Not getting much in the way of answers over there I'm afraid.
I have a new quest, to find out if I can use my US Sirius account on the iPod Touch. My sister has one (iPhone actually) and the only Sirius app in her app store is the Sirius Canada app - we installed it but my US sirius.com login was rejected - doh!
For the iPhone app, you would have to get it from the US Appstore to have it work.
Can you use the US Appstore if you are in Canada / bought your iPod/iPhone in Canada? Sorry, I know next to nothing about Apple products, and I really don't want to go out and buy one just to be disappointed.
You would have to sign up to the US AppStore with a US address and a US credit card.