Severus Snape;
Profiles and Info sites:
 

These links will take you directly to the site
and will open in a new window.

.
Snape's Profile
A general profile site of the Master of Snark himself.
From Lady Claudia's Why Snape? site.

A Snape reference/resource
A list of all Snape's conversations/interactions with other
adults in the books, without the audience of Harry & friends
(or, as in most cases, occasions where Snape didn't
know Harry or another student could overhear him).

The Severus Snape Essays
An excellent series of essays from Mugglenet's North Tower.
Written by Maline Fredon
Part 1: The Significance of PS/SS
Part 2: Losing Control
Part 3: The Vampire Rumours

 

Red Hen Publications
For the essays that are specifically Snape
oriented, check out the "Man on a
Tightrope" section in the links list
on the left of the page.

A good looking site with information both on Severus Snape,
and Alan Rickman.

Snape's Solice
This is definitely a fan-girl site.  Note the misspelling of
the word 'solace'.  (Update!  She's fixed the word
"solace!"  Good for her!  It still has the awful music, though.)
It also has some rather annoying music that
plays while you visit.  However, it has a plethora of pictures,
a fairly well written biography, and a short
list of Snape quotes from the books.