Mobile phone prefix?

Hi, I'm a computer programmer in Brazil.


I need to make a program to calculate phone bills.


I know every code to dial to any country in the world but I need to know how to differentiate phone calls to fixed phone and to mobile phone. Are there a world prefix to mobile phone? For instance, here in Brazil, every mobile phone start with prefix 9, 8 or 7. Which prefix is used in your country?

Mobile phone prefix?
They do have different prefixes for Mobile numbers, however, there are millions of cell phone users in the US. It would be easier to pick a city and go from there.