I was looking for an app that had the ability to gps track as well as have a good detailed topo map and came across Canada Topo Maps put out by Atlogis. The pro version which costs $6.4 just came out a couple weeks ago. Great relief shading and the ability to choose from a number of different maps. Has US topo maps in it too, plus a trip meter including time and distance travelled.
Gonna give it a try outdoors soon.
I have "topographical maps for Canada" for iPhone. Every map in Canada, free. Download the ones you want.
When you're in cell range, it will pinpoint your location in the map, allow you to determine distances, etc. I haven't played with it too much.