This is a rather stupid question I guess, but anyways:
From all what I've read, the difference between per-pixel lighting and per-vertex lighting is that the first is calculated per-pixel (sounds rather logical), speaking in the pixel shader.
Well, if this is right, are the shaders from the shader tutorial using per-pixel lighting then? If so, I understood it, if not, well, then I'm lost. Hope this question isn't too dumb.

As of how I understood it, this is correct. Thus per-pixel lightning gives a smoother and better looking result then vertex-lightning. The quality of the vertex lightning get's better, the more vertex a model has. Per-pixel lightning is slower then vertex lightning.

Yes. The difference is very small, however, with directional lights (such as the sun).

Jibb

EDIT: slightly ninja'd.

Okay, good that I understood it right then. Thank you.