One of my favorite applications on my iPhone is Trailguru, which I started using to track my bicycle rides. It's also a fun and simple way to track my flights.
Here's a summary of my flight this morning in the STOL CH 750.
Besides the mapping, it provides a quick overview of the elevation and speed:
Here's the website that logs the flight info:
There are other fun (and sometimes useful) applications for the iPhone for pilots. I like the live weather reports, though I haven't had much luck accessing these inflight...
Let me know what iPhone applications you use while (or before) flying...