BMW Repair: radio code, bmw 318, radio code

Question
I have a 92 BMW 318. When the battery want dead (left the key in the ignition) the radio stopped working. It now just says the word code. Do you know how I can find out what the code is and how to enter it?
Thank you

Answer
My code is in with my manual and there is a little book just for the radio which has the code attached inside that book.  If it isn't there you will likely have to call a dealership to look it up by the VIN# for you.  Then it is just a matter of punching in the code on the radio preset station #'s.  I would make sure I keep it once you get it, as you will need it every time the power goes out.  Hope this helps.