Bonobo Labs has Zilla: Digital Dashboard & HUD (iTunes Link) for the iPhone and iPod Touch in the iTunes App Store for FREE (regularly $2.99) for a limited time.

Put yourself behind the wheel of a supercar every day with Zilla, the in-car computer your ride should have come with! Graph your G’s as you accelerate, corner and brake. See your speed, tire loading and other performance stats change in realtime as you drive, with over 14 stunning gauges and readouts. Zilla uses the powerful sensors in your iPhone, all you have to do is put it in your car!

Add Zilla to your ride to entertain friends as you drive, or if you’re into seriously into cars you can use it as a powerful tool to measure your vehicle’s handling and performance.