Web Forums:

• LaTeX Community
  LaTeX-dedicated web forum: discussions about LaTeX, Distributions, Editors
• CQF.info
  LaTeX subforum of the CQF board
• Art of Problem Solving
  (LaTeX subforum)
• mrunix.de
  LaTeX subforum of the mrunix board, well frequented
• Textsatz mit LaTeX
  subforum of matheplanet.com, a big german math site
• Apfeltalk
  office applications subforum of the german apple mac forum containing LaTeX discussions, helpful for mac users
• Chemie online
  LaTeX subforum of chemistry discussion board
• MatheBoard
  subforum of the math board
• Mathe-Raum
  subforum of the Mathe-Raum math board
• goLaTeX
  german LaTeX forum, online since June 08

Usenet groups:

• comp.text.tex
  usenet discussion group for TeX and LaTeX
• de.comp.text.tex
  german usenet discussion group for TeX and LaTeX