The app I use is I believe available for Android, iOS, and soon for Windows phone. It's called Bikecomputer pro and costs just over £3. It can import GPX files, and will show their track and simultaneously the track that's been followed by the bike. Makes navigating a planned route a doddle.
It also has all the usual speed, average speed, max speed, distance, ride time - and so on - functions.
It can take downloadable offline maps, which means it works where there's no phone signal and doesn't run up a data bill.
Only issue is that the demo video is only available in German so if like me you don't speak German that's no use!
As I said earlier the drawback is that to keep the app running and on-screen continuously for more than about 4 to 5 hours needs help from an external battery pack.