I'd get a card reader. It's faster and less trouble than a direct connection. I think the 1D only has a Firewire port, so you'd need a Firewire cable and a computer with a Firewire port also.
Adorama do seem to sell the cable -
http://www.adorama.com/Refby.tpl?refby=rflAID012417&sku=ICAIFC200D6 but the picture they have on their website is wrong. I suspect they sell the right cable and have simply put the wrong picture up.
Personally I use a Sandisk High Speed Card Reader to transfer my images. It's very fast and has worked without a hitch. If will also work with the CF card from your XTi
Take a look at this article for more about card readers and some suggestions about what to get
http://www.bobatkins.com/photography/digital/sandisk_compact_flash_card_readers.html