From the FAQ on TiVo’s website:
Is the TiVo service available in Canada?
The TiVo Service is now available in Canada. There are special instructions for Canadian residents to follow when activating service.TiVo does not sell boxes in Canada, so Canadian residents must purchase boxes in the US and import them. If the DVR becomes defective, TiVo will not ship a warranty replacement box into Canada, and will only ship to a US address.
So they don’t have retail distribution in Canada (yet), but you can use the boxes there. So no more hacking required to use TiVo for our friends to the north!