The default FOV in BC2 is 60, which is 5 degrees lower than in CoD: MW2 for comparison.
With an FOV below ~80 or 90 you can barely see whats next to you.

BC2 uses Punkbuster instead of Valve Anti Cheat.
You will not recieve a PB or VAC ban.

I recommend a FOV of 85 or more.
I play most games with an FOV between 90 and 110.
A very high FOV could cause motion sickness or (cluster) headaches.

Go to "[DRIVE]\Users\[YOUR USER NAME]\Documents\BFBC2" and open the "settings.ini" with notepad++ (you can use the default text editor, but I highly recommend notepad++[notepad-plus-plus.org]).

Then in the last line in "graphics" there should be "fov=60".
Change 60 to your desired FOV, save it and set as "read only".

1. Right click on the file, you want to make it Read-only.
2. Click on the Properties tab from the context menu.
3. Click the Read-only check box belong to Attributes from on the General tab from the popped up Properties window.
4. Click on Apply and then click on Okay.

Alternatively, there is the Bad Company 2 Launcher from Gossamer, which allows you to change a whole range of options such as resolution, refresh rate, DirectX version and the FOV.
I haven't tested it, so I can't guarantee that it works, but there's nothing to say against it.

Gossamer's Bad Company 2 Launcher on ModDB

Changing the FOV seems to work in multiplayer only.
I am NOT the support of the game! For troubleshooting contact the developer!