I routinely shop for bike parts at MX Bike, BikeBandit and RockyMountain and have them ship to my own physical US address in Ogdensburg, NY, only 40 minutes from Ottawa. I pick up my packages and declare them myself and save quite a bit of money by avoiding the super high UPS and Fedex brokerage fees
Compared to other such US address services, myusaddress.ca offers so much more - email notifications/SMS text notifications when packages arrive, a secure pickup service (I am not rooting thru piles of other people's packages) and I can even opt to have these guys clear my items across the border and I pick up in Prescott (saves me having to pay $6 CAD to get across that bridge - which has been under construction all summer). Another appealing aspect of this Canadian-based service is that they deal in Canadian funds. No need to have US currency.
Check them out: http://myusaddress.ca