In addition to the sources mentioned above, LaTeX has its home page on the World Wide Web at:
http://www.tex.ac.uk/CTAN/latex/This page describes LaTeX and the LaTeX3 project, and contains pointers to other LaTeX resources, such as the user guides, the TeX Frequently Asked Questions, and the LaTeX bugs database.
More general information, including contacts for local User Groups, can be accessed via:
http://www.tug.org/
The electronic home of anything TeX-related is the Comprehensive TeX Archive Network (CTAN). This is a network of cooperating ftp sites, with over a gigabyte of TeX material:
ftp://ftp.tex.ac.uk/tex-archive/ ftp://ftp.dante.de/tex-archive/
For more information, see the LaTeX home page.