see this thread,
http://forums.ubi.com/showthread.php...-in-widescreen
you will have the black bars in the menus but not in game.
However, unless you use Sans FOV changer or if you run a mod version of the game and use one of the FOV mods you will loose some FOV. (this is what i do to get the same FOV back as when you use a 4:3 aspect monitor, FOV you need is 101).