I've just started using an app called Cyclemeter by Abvio, and I've found it to be really excellent so far. Sells for $4.99.

You can import GPX, KML, or CSV data for routes. I haven't imported any routes yet, so I can't comment too much on this feature.

The rest of the app is really great for tracking your ride and it provides you with a nice graphic and data at the end of each ride. There's a ton of features to customize in the app for whatever you wish to track during and post ride.

Here's a couple of my rides, one road and one mountain, for you to check out:

- Road ride around Zugersee
- Mountain ride around Lenzerheide

You can stop and start the app manually, or set it to auto stop when you stop during your ride. The Lenzerheide ride I let run for the day so it includes chairlift and gondola rides, etc. Kind of interesting to see your entire path for the day.

Bottom line, I very happy with it to date and highly recommend it.