As AG suggests, there are plenty of websites which offer to provide radio codes (for a fee). However they're not always reliable. Additionally, you'll have to remove the radio (which can be extremely difficult, sometimes requiring special tools) in order to find the make, model number and the serial number of the radio.
If you go to any Ford main dealer (or, indeed to any local garage, who will then contact a main dealer), they will almost certainly be able to get the code simply from either the registration number or the chassis number of the car. (I work for a Ford main dealer who provide radio codes every day). Ford charges dealers for providing radio codes and, of course, dealers add on a profit margin. The firm I work for charges customers about £15.
Chris