12 volt battery level measurement

Hi,
For my project I have to find a 12 V battery level measuring circuit. When I looked at www I coulnd't find a specific application. I want a simple version to implement to my project easily. I want that would be in the same theory with the battery level measuremnts like in cellular phones.
Thanks to all....

Checkout the LM3914/5 IC's These bargraph IC's are just the job, I'm sure I've seen these used for car battery monitoring somewhere. I think you just suppress the lower 10 volts, so you get useful readings between 10 & 15 Volts. Try national's site 1st.

Steve