Voldemort, Voldemort, Voldemort. I love that name.
Anyway, didn't Dumbledor at some point say it was because he used dark magic to warp his appearance? Doesn't he have a forked tongue too in the Goblet of Fire film?
And... I don't recall in the books too much discription on his appearance prior to the movies. It was quite vague. I think its the movies that sort of warped the character's looks to what he is now, and in later books, like the slit nose and such. I don't recall the books ever referring to him with snakelike features, only probably later in the books, after his movie appearances. I need to keep reading...
On a side note with him the movies, why does he go barefoot...? That I wonder...