Speedometer is a nifty US$1.99 universal iOS app that provides a speedometer for cars and cycling, as well as start times, time elapsed, distance, average speed, maximum speed and your altitude.
The app also features a map mode where you can see your starting point and current position, and a share button to email your current position information. In addition, Speedometer provides your latitude and longitude, and an indication of how accurate the GPS information is. A compass gives you your direction in degrees, and more generally, like NW or SE.
I tried the app on a short test drive and found it worked as expected and it provided helpful information, more than most navigation programs provide. Living in the foothills of mountains, I especially liked the altitude readout.