TrailGuru is another great app for those of you who like to get fit with your iPhone. There are plenty of options on here for more than just runners, which many of the other apps have unfortunately limited themselves too. Plus, you can actually upload all of your stats to a community site to share what you've accomplished and routes you've taken.
The main screen of the app keeps track of how far you've gone, how long you've been going, and you're location (latitude and longitude). All of this information tends to be fairly accurate as long as you're in an area where you have full cell phone service. Once you complete your trail all you need to do is name it and select how you conquered that trail.
You do have to manually register for the site to take full advantage of this app. It will exit you out into Safari to do so as well. When you're on your trail, if you receive a phone call or lose reception, the app basically falls apart and stops tracking the information accurately. Even on EDGE it does seem to struggle at doing it's task. So unless you're a big fan of taking a trail located around a 3G tower, you may not find this app too useful.
TrailGuru gives you a chance to differentiate what method of trailblazing you decided to use. This is great for keeping notes and of course reading through others in your area too, so that you can find the best possible trail in your area. A lot more of the functionality comes from using the off site aspect of this app unfortunately, so for now it may be best to stick with whatever tracking app you've been using.