State Farm has just released an iOS application called Driver Feedback. The app uses your iDevice's accelerometer and GPS to "grade" your driving.
It monitors the three driving behaviors that are the riskiest, and thus need to be tracked are hard acceleration, hard braking, and hard cornering. Since we know that iPhone is very good at tracking users, it's an obvious choice, but it would be nice to see an Android version, as well.
As you might expect, it's free in the App Store. Just to be clear, State Farm said it does not collect the trip information. Additionally, the data recorded by the app will not impact your insurance rates (particularly since you don't have to be a State Farm customer to use it).
Here are the features:
Record driving using your device’s accelerometer and GPS location (GPS not available on iPod touch)
View all alerts in a list view or overlaid on a map
Compare two trips against each other
Send trip results via email and SMS
Support for multiple users
Although it's designed with the end user in mind, we can see this app being used by parents, to check on the driving behaviors of their teenagers, for example. Since results can be sent by email or SMS, you don't even need to confront your teen at the end of their trips.