I have been playing with an app called Race Q's lately.
It produces a track of your sail boat race. When multiple boats upload a track in the same area at the same time it assume you are all in the same race. This allows you to analyze your performance against others and help you improve. Here's their promotional video:
I am also enjoying the raceq's podcast. It has some really good learn to race material. Find it here:
Here is a link to the rest of the podcasts in itunes.
When you go to replay a regatta using the app consider using an alternative browser to Firefox. Firefox seems to have some issues with the Google earth imagery used in the app.