Our company has just such an app in beta right now. It will run silently on the phone and the settings will be able to be set from a web page. You will be able to track current location as well as history. It will give speed and direction as well.Other features include
1. Proximity Alert
Set a point on the map and a distance and get notified when they break the barrier.
2. Electric Fence
Set a boundary around a point and get notified when they go outside of it.
3. Texting Alerts
Set a speed and get notified if the phone sends a text while exceeding it.
This should be available for public use by April 15th 2011. Please visit our website and or send me an email if interested. firstname.lastname@example.org