First ... read any FAQ you can find. (Which is what you're doing now, isn't it?)
An ambitious FAQ-like project to collect all TeX-related
information into one place is under way at
http://www.ctv.es/USERS/irmina/TeEncontreX.html; as with any
FAQ, this project needs the support and help of all users -
as yet, it carries an incomplete set of answers to potential
questions. The sources of the package (including a complete set of
html files) are available on CTAN
The tutorials and other on-line documentation (see (La)TeX Tutorials) can get you started but for more in-depth understanding you should get and read at least one of the many good books on the subject (see TeX-related books). The definitive source for (La)TeX is the source code itself, but that is not something to be approached lightly (if at all).
If you are seeking a particular package or program, look on your own system first: you might already have it - the better TeX distributions contain a wide range of supporting material.
If you have access to the internet, and in particular newsgroups, then (La)TeX discussions, including Metafont and MetaPost, are on comp.text.tex. It is best to spend a little time familiarising yourself with the current threads before asking a question. The group is normally very responsive but asking a question that has just been answered is likely to dampen people's enthusiasm to help you.
http://groups.google.com/ archives Usenet news discussions, and comp.text.tex may be found there. Google's archive now goes impressively far back in time (before comp.text.tex even existed), and it is a powerful resource for tracking down that recommendation that no-one can now remember. Google also now allows you to post your own questions or followups.
The few people who can't use the World Wide Web, can't access Usenet news, but can use electronic mail can seek help through mailing lists.
The TeXhax digest is nowadays operated as a moderated "MailMan" mailing list: its members now have the option of receiving messages in 'real time', and answers are more quickly forthcoming than ever they were in the past. Subscribe via http://lists.nottingham.ac.uk/mailman/listinfo/texhax; past digests are available on CTAN.
Many mailing lists exist that cover some small part of the TeX arena. A good source of pointers is http://www.tug.org/
Announcements of TeX-related installations on the CTAN
archives are sent to the mailing list ctan-ann. Subscribe
to the list by sending a message
'subscribe ctan-ann <your email address>' to
majordomo@dante.de
Issues related to Metafont (and, increasingly, MetaPost) are discussed on
the metafont mailing list; subscribe by sending a message
'subscribe metafont <your name>' to listserv@ens.fr
A few other TeX-related lists may be accessed via
listserv@urz.uni-heidelberg.de. Send a message containing
the line 'help' to this address, or browse
http://listserv.uni-heidelberg.de/cgi-bin/wa