There's a lot of documentation, tutorials, etc. out there that was not written by the LaTeX team themselves. We've started a list pointing to some of it (the order is fairly arbitrary and no indication of quality).
If you know about a great resource for TeX and related documentation not listed here, please contact us.
Frequently Asked Questions (FAQ) for English-speaking users of TeX
The information is maintained by a group of “curators”, with contributions from a very wide range of people over
many years. It has its origin in the UK TeX FAQ.
The questions answered here cover a wide range of topics, but typesetting issues are mostly covered from the viewpoint of a LaTeX user.
A Visual LaTeX FAQ
Having trouble finding the answer to a LaTeX question? The Visual LaTeX FAQ is an innovative new search interface that presents over a hundred typeset samples of frequently requested document formatting. Simply click on a hyperlinked piece of text and the Visual LaTeX FAQ will send your Web browser to the appropriate page in the TeX FAQ. By Scott Pakin.
TeX Users Group
The TeX Users Group web site (International).
Dante - Deutschsprachige Anwendervereinigung TeX (German)
The web site of German TeX Users Group. You will find a lot of information and tutorials.
Gutenberg (French)
The web site of the French speaking TeX Users Group. You will find publications, tutorials and more.
UK-TUG
The web site holding the archives the UK TeX Users Group. UKTUG is no longer in existance but the archive holds interesting historical material. They also published a lot of their meeting sessions
as videos.
TeX user groups around the world
There are many more user groups on TeX — most certainly one close to you …
A listing of (all/most) TeX user groups around the world is maintained by the TeX Users Group.