LaTeX: Errors

Here is a webpage I found that has helpful LaTeX or TeX errors (the common errors, I suppose), and what they usually refer to.

Mysterious TeX Errors: http://www.tug.org/errors.html

Edit/Update: 7-7-11

I thought I had linked this page before. Here is a list of error classes. This list provides the error message, it's class, and the cause of the error. Two tables, one for ambiguous errors and the other for common errors.

Latex Error Classes - http://www.cs.utexas.edu/~witchel/errorclasses.html