Charlie and Claire are both right.....it's all a matter of degree. You can get some perspective correction in the darkroom - but if it's waaaaaay out you are not going to make it look right. Like any other aspect of shooting you want to get it as right as you can at the camera, and spend your time in the darkroom wringing the best out of a good negative, not trying to fix poorly shot negs. Back when I worked in the studio, I spent a lot of time trying to make prints that would meet the client's requirements from stuff some of the guys shot very sloppily. It's a PIA!!! And it's never going to be as good as if you put in the effort at the camera.
Just my tuppence.
Bob