FOV doesn't do much so idk why you would want this but the address is 2FF6888. Just got the address today so if should be fresh and not patched. Tutorial to put it in:
1) Open cheat engine(if you dont have it, get it, it is one great program!)
2) Click the button in the Lower Right corner called "id Address Manually"
3) Set Type to Float and select Pointer
4) Where it says 0 replace it with 18
5) Paste the 2FF6888 in box underneath the 0
6) Hit ok and run BlackOps! The value should come out to be 65(default value) if you did everything right
7) If this works for you, please give thanks and rep++++ :P