there is a app for the iphone called navonics it is a gps for the lakes of ontario I have used it for 2 yrs now and it works just like any gps . tells u depth, saves waypoints where the marinas are and much more and the greatest thing of all its only $ 9.99 under ten bucks
I'll second that being a VERY handy app! I have the North American Marine Charts version, cost me $15. I didn't see a version just for Canada. One downside is that it's pretty hard on the already useless battery in the Iphones. Would make a great app on an Ipad with a case and dash mount!