Although I haven't used it while running, I like Trailguru. It locates you pretty easily. If you sign up for a login at the Trailguru website you can upload your route up to the website. That's pretty cool.
I'm using Distance Meter, which a paid app. It does pretty much everything Trailguru does. It also has a calorie meter, showing you how many calories you burned. Distance Meter uploads its stats and GPS to MapMyFitness.com.
I noticed that MapMyFitness.com has other sites like MapMyRun.com and has developed their own iPhone apps. I think they were free and you might want to check them out.