If you like to hike in trails without a map, this iPhone application is available on the AppStore.
eGtretel tracks your position in real time, and puts a pin (a "breadcrumb") along your path.
Just like in the "Hansel and Gretel" and "Tom Thumb" fairytales, if you get lost, just follow the breadcrumbs to find your way back to civilization.
This application tracks the time each breadcrumb was dropped along with its location. You can send these locations and times by email.
eGretel is not limited to hiking. You can use it to measure the time you take to go to work and for each segment of road you take. You can also use it to time your performance in a car race track.
Please note that this application tracks your location, and is configured to run in the background. Continued use of GPS running in the background can dramatically decrease battery life.
For troubleshooting, see the support page.