http://www.insightcentral.net/KB/faq-accessories.html

Another option is 3M's "invisible bra" - a clear film that can be applied to the front bumper and hood to protect them from stone chips, etc. This film could also be used on other parts of the car that are subject to wear & tear, such as the bottom of the door frame.

see link provided above for further details (to include where to buy, etc.).