Push in the R3 button (For PS3) and move the camera around while pushing it in to where ever you want....I perfer a view right over my shoulder in 3rd person so I can look down the barrel of the gun and move around quickly..
yeah i'm pretty sure you can, i mean i haven't seen it confirmed anywhere but i don't think it's likely to change from fallout 3, seeing as they're still using the same graphics engine as well...