In Windows, search for
settings.ini in your Documents folder.
For me in Win7 it can be found in
C:/Users/Nod/My Documents/BFBC2.
Now, open
settings.ini in notepad or some other text editor. At the bottom you see
Fov=, 55 I think being the default setting. Change the value; mine is set at 100 with
a 1280 * 1024 resolution, which is not recommended by most people that tweak their
graphics, but is what I like best.
You can find BFBC2 FOV Calculators on the web
like
this one if you need help.