Solution 1:

If by FPS you mean the frame rate at which a video is played, you can access that information while playing by clicking on Tools >>> Codec information. In the video stream there should be a row with that information. (I'm basing myself on a Windows 2.0.2 version but it should also be valid for any other GUI).

If on the other hand you're looking for a overlaid FPS display I believe VLC doesn't do that, as mentioned before, but there should be some third party solutions.