This was I think an old Asian movie. I don't know if it was 60's or 80's, but it had that "old" look.

I don't remember any of it except what I believe to be the last scene.

In it, I think the people are in a school or... a boarding house... something big like a mansion with many halls and doors. Anyway, there is this weird woman/monster and her neck extends and her head follows the victim throughout the building, the neck growing and twisting around corners and stuff.

It was night time. It was really dark throughout.

That's all I recall. =\

Possibly 100 Monsters. If you scroll down a bit, there's some pictures of the woman with the long neck.
God Bless the Japanese
Here's a clip: http://www.youtube.com/watch?v=invKpFNn9jc

Hmm, I sure don't know if that's it, but it looks like it might be. Just rented the movie on Netflix. I'll letcha know. Thanks. Something to work with. =)