Also try GPS MotionX. Will give you lots of options and has worked pretty well for me.
+1
i haven't fully used it yet. but, i turned it on during last weekend's ride, which i unfortunately had to turn around and come back b/c [1] my bike was acting up and [2] one of the riders crashed.
so, i doubled-back by turning around in the middle of the street (no traffic. country road). when i inally got home and thought to check if the app tracked well, it was so accurate it perfectly tracked my u-turn from one side of the narrow road to the other! i was impressed, but more testing is in order.