From Path Tracker:
Record your path, save it to the web, and share it with friends!
Path Tracker displays the distance you've traveled, elapsed time, average speed, latitude, longitude, and altitude.
On PathTracks.com you can view your paths in Google Maps, export your paths as KML or GPX, and view your speed and pace at every GPS point.
Perfect for recording your route while walking, running, hiking, biking, skiing, snowboarding, boating or traveling on any kind of trip.
Path Tracker turns your iPhone into a speedometer, odometer, stopwatch, altimeter, GPS location tool, and training buddy.
Take Path Tracker on your next walk, run, bike, or hike.
+ Turn off real-time maps to avoid data usage and extend battery life.
+ Saves your path automatically, so you can continue after a phone call.
+ Choose miles or kilometers.
+ View normal, satellite, or hybrid map.
Path Tracker works best on the iPhone 3G with built-in GPS. It will not be very accurate on the original iPhone or iPod touch, which don't have built-in GPS. All updates are free.
* Do not lock your iPhone or turn off the screen by pressing the top button. The iPhone turns off GPS when it is locked.
* Turn off auto-lock. In most cases, Path Tracker automatically disables auto-lock while it is running. However, if you receive any kind of alert (calendar alert, SMS alert, battery level warning) and do not dismiss the message, the iPhone will auto-lock and turn off GPS. To avoid this, open the "Settings" app, tap "General", tap "Auto-Lock", and select "Never".
* For best battery life: Set screen brightness to lowest setting, turn real-time maps off, turn 3G off, turn WiFi off, and turn data push off.
* Reboot your iPhone before starting a path to free up the most memory. After being turned on for too long, the iPhone starts to run low on application memory even if no apps are open.
* Click the "Path Tracker Support" link below for more help.
Thank you Apple for creating this incredible platform!